TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Diels-Alder reaction of leaving group-containing compound of formula: A1=A2, and pentacene compound of formula (III) is carried out. The obtained reaction product is aromatized in the presence of dehydrogenation reagent to obtain pentacene adduct (I). Preferred Method: Diels-Alder reaction of leaving group-containing compound of formula: A1=A2, and pentacene derivative (II) is carried out to obtain pentacene adduct (I). Preferred Definitions:    A1+A2=ring chosen from group of formula (i)-(iv), preferably chosen from ring(s) of formula (v)-(viii), or functional group of formula (ix)-(xi);    Q=oxygen atom, sulfur atom or group of formula: -N(Ra)-;    ring A=6-20C optionally substituted monocyclic or polycyclic aromatic ring;    X1-X4=halo or cyano;    wavy line=connecting point with pentacene structure;    R=optionally substituted 1-20C alkyl, alkenyl or alkynyl;    R5,R12=optionally substituted silyl;and    R1-R4,R6-R11=H.    SPECIFIC COMPOUNDS - 32 Pentacene adducts (I) are disclosed e.g. 7,8,9,10,14,19,20,21-nonapraseodymio-25-oxaheptacyclo(14.6.5.02,15.04,13.06,11.017,22.023,27)heptacosa-2,4,6,8,10,12,14,17(22),18,20-decaen-18-yl)praseodymium of formula (Ia), (18,25-dioxo-7,8,9,10,14,28,29,30,31-nonapraseodymiooctacyclo(14.10.6.02,15.04,13.06,11.017,26.019,24.027,32)dotriaconta-2,4,6,8,10,12,14,19(24),20,22,27(32),28,30-tridecaen-3-yl)praseodymium, (25,26-dichloro-23,28-dicyano-24,27-dioxo-3,7,8,9,10,14,19,20,21-nonapraseodymioheptacyclo(14.6.6.02,15.04,13.06,11.017,22.023,28)octacosa-2,4,6,8,10,12,14,17(22),18,20,25-undecaen-18-yl)praseodymium, (23,25,26,28-tetrachloro-24,27-dioxo-3,7,8,9,10,14,19,20,21-nonapraseodymioheptacyclo(14.6.6.02,15.04,13.06,11.017,22.023,28)octacosa-2,4,6,8,10,12,14,17(22),18,20,25-undecaen-18-yl)praseodymium and (23,24-dioxo-7,8,9,10,14,18,19,20,21-nonapraseodymiohexacyclo(14.6.2.02,15.04,13.06, 11.017,22)tetracosa-2,4,6,8,10,12,14,17(22),18,20-decaen-3-yl)praseodymium.    EXAMPLE - Dihydrodeca propyl pentacene (92 mg), maleic acid anhydride (26 mg) and toluene (3 mL) were added to tube, and mixture was stirred at 50 degrees C for 4 hours. Then, mixture was heated at 80 degrees C and stirred for 11 hours. The solvent was distilled off under reduced pressure. Then, column chromatography was performed using silica gel as a filler. The obtained compound was processed in 100 degrees C toluene using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (13 mg). Solvent was distilled and residue was purified. 7,8,9,10,14,19,20,21-nonapraseodymio-25-oxaheptacyclo(14.6.5.02,15.04,13.06,11.017,22.023,27)heptacosa-2,4,6,8,10,12,14,17(22),18,20-decaen-18-yl)praseodymium was obtained at yield of 96%.