TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The 3-arylbenzofuranone stabilizers are compounds of formula (I). The hindered amine light stabilizers contain at least one piperidine moiety of formula (V) (preferably condensate of 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid; linear or cyclic condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-triazine; linear or cyclic condensates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine; linear or cyclic condensates of N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine; linear or cyclic condensates of N,N'-bis-(1,2,2,6,6-pentamethyl-4-piperidyl)-hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine; condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane; the condensate of 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-tri- azine and 1,2-bis-(3-aminopropylamino)ethane; reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro(4,5)decane and epichlorohydrin; poly(methyl,(3-oxy-(2,2,6,6-tetramethylpiperidin-4-yl)propyl)) siloxane; reaction product of maleic acid anhydride-18-22C alpha-olefin-copolymer with 2,2,6,6-tetramethyl-4-aminopiperidine; oligomeric compound which is the condensation product of 4,4'-hexamethylene-bis(amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-((2,2,6,6-tetramethylpiperidin-4-yl)butylamino)-s-triazine end-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine; oligomeric compound which is the condensation product of 4,4'-hexamethylene-bis(amino-1,2,2,6,6-pentaamethylpiperidine) and 2,4-dichloro-6-((1,2,2,6,6-pentaamethyl-piperidin-4-yl)butylamino)-s-triazine end-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine; oligomeric compound which is the condensation product of 4,4'-hexamethylene-bis(amino-1-propoxy-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-((1-propoxy-2,2,6,6-tetra-methylpiperidin-4-yl)butylamino)-s-triazine end-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine; oligomeric compound which is the condensation product of 4,4'-hexamethylene-bis(amino-1-acyloxy-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-((1-acyloxy-2,2,6,6-tetra-methylpiperidin-4-yl)butylamino)-s-triazine end-capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine and product obtained by reacting a product, obtained by reacting 1,2-bis(3-amino-propylamino)ethane with cyanuric chloride, with (2,2,6,6-tetramethylpiperidin-4-yl)butylamine)). The hindered amine is N-H, N-methyl, N-methoxy, N-propoxy, N-octyloxy, N-cyclohexyloxy, N-acyloxy or N-(2-hydroxy-2-methyl-propoxy) substituted amine. The hindered phenolic antioxidants are selected from butylated hydroxytoluene, butylated hydroxyanisole, tocopherol, benzylphosphonates, esters of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, esters of beta-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols and esters of 3,5-di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols.R1=Q1, phenylene, naphthylene (both optionally substituted by 1-4C alkyl- or hydroxy) or -R12-X-R13-;Q1=naphthyl, phenanthryl, anthryl, 5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl, benzo(b)thienyl, naphtho(2,3-b)thienyl, thianthrenyl, dibenzofuryl, chromenyl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, beta-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl, biphenyl, terphenyl, fluorenyl or phenoxazinyl (optionally substituted by 1-4C alkyl, 1-4C alkoxy, 1-4C alkylthio, hydroxyl, halo, amino, 1-4C alkylamino, phenylamino or di(1-4C alkyl)amino) or phenyl substituted at position 2, 3, 4, 5 and 6 by R7, R8, R11, R10 and R9 respectively;R2, R3 and R5=Q;Q=H, Cl, hydroxyl, 1-25C alkyl, 7-9C phenylalkyl, phenyl (optionally substituted by 1-4C alkyl), 5-8C cycloalkyl (optionally substituted by 1-4C alkyl), 1-18C alkoxy, 1-18C alkylthio, 1-4C alkylamino, di(1-4C alkyl)amino, 1-25C alkanoyloxy, 1-25C alkanoylamino, 3-25C alkenoyloxy, 3-25C alkanoyloxy (optionally interrupted by O or S), 6-9C cycloalkylcarbonyloxy or benzoyloxy (optionally substituted by 1-12C alkyl);R4=Q, -(CH2)p-COR15, -(CH2)qOH or benzofuranone compound of formula (III);R2+R3, R3+R4 and R4+R5=benzo ring;R6=H or benzofuranone compound of formula (IV);Q2=Q, -(CH2)p-COR15 or -(CH2)qOH;R7-R11=H, halo, hydroxyl, 1-25C alkyl (optionally interrupted by O, S or -N(R14)-), 1-25C alkoxy, 2-25C alkoxy (optionally interrupted by O, S or -N(R14)-), 1-25C alkylthio, 3-25C alkenyl, 3-25C alkenyloxy, 3-25C alkynyl, 3-25C alkynyloxy, 7-9C phenylalkyl, 7-9C phenylalkoxy, phenyl (optionally substituted by 1-4C alkyl), phenoxy (optionally substituted by 1-4C alkyl), 5-8C cycloalkyl (optionally substituted by 1-4C alkyl), 5-8C cycloalkoxy (optionally substituted by 1-4C alkyl), 1-4C alkylamino, di(1-4C alkyl)amino, 1-25C alkanoyl, 3-25C alkanoyl (optionally interrupted by O, S or -N(R14)-), 1-25C alkanoyloxy, 3-25C alkanoyloxy (optionally interrupted by O, S or -N(R14)-), 1-25C alkanoylamino, 3-25C alkenoyl (optionally interrupted by O, S or -N(R14)-), 3-25C alkenoyloxy (optionally interrupted by O, S or -N(R14)-), 6-9C cycloalkylcarbonyl, 6-9C cycloalkylcarbonyloxy, benzoyl (optionally substituted by 1-12C alkyl); benzoyloxy (optionally substituted by 1-12C alkyl), -OC(R18)(R19)C(=O)R15 or -OCH(R20)C(R21)(R22)OR23;R7+R8 and R8+R11=benzo ring;R12 and R13= phenylene or naphthylene (both optionally substituted by 1-4C alkyl);R14=H or 1-8C alkyl;R15 and R28=hydroxyl, -O- 1/r(M(raised to r+)), 1-18C alkoxy or -N(R24)(R25);R16 and R17=H, CF3, 1-12C alkyl or phenyl;R16+R17=5-8C cycloalkylidene (optionally mono- to tri- substituted by 1-4C alkyl);R18 and R19=H, 1-4C alkyl or phenyl;R20=H or 1-4C alkyl;R21=H, phenyl (optionally substituted by 1-4C alkyl), 1-25C alkyl, 2-25C alkyl (optionally interrupted by O, S or -N(R14)-) or 7-9C phenylalkyl (optionally mono- to tri-substituted on phenyl ring by 1-4C alkyl and interrupted by O, S or -N(R14)-);R20+R21=5-12C cycloalkylene (optionally mono- to tri-substituted by 1-4C alkyl);R22=H or 1-4C alkyl;R23=H, 1-25C alkanoyl, 3-25C alkenoyl (optionally interrupted by O, S or -N(R14)-), 2-25C alkanoyl substituted by di(1-6C alkyl)phosphonate, 6-9C cycloalkylcarbonyl, thienoyl, furoyl, benzoyl (optionally substituted by 1-12C alkyl), -C(O)CsH2s(A1), -C(O)CH2SCH2(A1), -C(O)CH2C(CH3)(A1)2, -C(O)R27C(O)R28 or -C(O)R29R30;A1=phenyl (substituted by tert-butyl at 3-position, by OH at 4-position and by R26 at 5-position);R24 and R25=H or 1-18C alkyl;R26=H or 1-8C alkyl;R27=a direct bond, 1-18C alkylene, 2-18C alkylene (optionally interrupted by O, S or -N(R14)-), 2-18C alkylene, 2-20C alkylidene, 7-20C phenylalkylidene, 5-8C cycloalkylene, 7-8C bicycloalkylene, phenylene (optionally substituted by 1-4C alkyl), furan-2,5-diyl or thiophene-2,5-diyl;R29=O, -NH- or -N(C(O)NHR30)-;R30=1-18C alkyl or phenyl;R31=H or 1-18C alkyl;M=r-valent metal cation;X=a direct bond, O, S or -NR31-;n=1 or 2;p and s=0-2;q=1-6;r=1-3;G1-G5=1-8C alkyl; andG1+G2 and G3+G4=pentamethylene.Provided that:(1) when n is 1, then R1 is Q1;(2) when n is 2, then R1 is phenylene, naphthylene (both optionally substituted by 1-4C alkyl or hydroxy) or -R12-X-R13-; and(3) when R3, R5 and R6 are H, then R4 is benzofuranone compound of formula (III). Preferred Definitions:    R1=naphthyl, biphenyl, terphenyl, phenanthryl, anthryl, fluorenyl, carbazolyl, thienyl, pyrrolyl, phenothiazinyl or 5,6,7,8-tetrahydronaphthyl (all optionally substituted by 1-4C alkyl, 1-4C alkoxy, 1-4C alkylthio, hydroxy or amino), phenyl (optionally substituted in para-position by 1-18C alkylthio or di(1-4C alkyl)amino), mono- to penta-substituted alkyphenyl containing together a total of at most 18 carbon atoms in the 1 to 5 alkyl substituents or -R12-X-R13-;    R13=phenylene;    X=O or -NR31-; and    R31=1-4C alkyl.    Provided that when n is 1, then R1 is naphthyl, biphenyl, terphenyl, phenanthryl, anthryl, fluorenyl, carbazolyl, thienyl, pyrrolyl, phenothiazinyl or 5,6,7,8-tetrahydronaphthyl (all optionally substituted by 1-4C alkyl, 1-4C alkoxy, 1-4C alkylthio, hydroxy or amino), phenyl (optionally substituted in para-position by 1-18C alkylthio or di(1-4C alkyl)amino) or mono- to penta-substituted alkylphenyl containing together a total of at most 18 carbon atoms in the 1 to 5 alkyl substituents; and when n is 2, then R1 is -R12-X-R13-.    SPECIFIC COMPOUNDS - 9 Compounds are specifically claimed as 3-arylbenzofuranone stabilizers, e.g. 3-(4-(2-acetoxyethoxy)phenyl)-5,7-di-tert-butyl-benzofuran-2-one; 5,7-di-tert-butyl-3-(4-(2-stearoyloxyethoxy)phenyl)benzofuran-2-one; 3,3'-bis(5,7-di-tert-butyl-3-(4-(2-hydroxyethoxy)phenyl)benzofuran-2-one); 5,7-di-tert -butyl-3-(4-ethoxyphenyl)benzofuran-2-one and 3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-tert-butylbenzofuran-2-one. 34 Compounds are specifically claimed as hindered amine light stabilizers, e.g. 1-cyclohexyloxy-2,2,6,6-tetramethyl-4-octadecylaminopiperidine, bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-acetoxy-2,2,6,6-tetramethylpiperidin4-yl) sebacate, bis(1,2,2,6,6-pentamethyl-4-yl) sebacate and bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate (Ia).    EXAMPLE - No suitable example given.