TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Group: The RAFT functional group is chosen from trithiocarbonate, dithiocarbamate, dithiocarbonate and dithioester. The conducting or semiconducting segment is a terminal segment of the polymer.    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The polymer is of formula: Q'(-L'-P'-S-C(=S)-Z')m or Q'L'-P'-S-C(=S)-S-P'-L'-Q'.m=positive integer, preferably 1-10, more preferably 1;Q'=m-valent conducting or semiconducting segment;L'=covalent bond or a linking group;P'=polymer segment having an insulating polymer backbone;andZ'=group that allows the polymer to function as a macro-RAFT agent in the polymerization of ethylenically unsaturated monomers, which comprises conducting or semiconducting segment and polymer segment.Preferred Segment: The polymer segment having insulating polymer backbone is product of polymerization of ethylenically unsaturated monomers of formula: W'-CH2(-H)=CH2(-U)(-V').U,W'=-CO2H, -CO2R2, -COR2, -CSR2, -CSOR2, -COSR2, -CONH2, -CONHR2, -CONR22, H, halo or optionally substituted 1-4C alkyl;V'=H, R2, -CO2H, -CO2R2, -COR2, CN, -CSR2, -CSOR2, -COSR2, -CONH2, -CONHR2, -CONR22, NHC(O)R2, NR2C(O)R2, PO(OR2)3, -OR2, -SR2, -O2CR2, -SCOR2,-OCSR2 or halo;andR2=1-22C alkyl, 2-22C alkenyl, 2-22C alkynyl, aryl, heteroaryl, carbocyclyl, heterocyclyl, aralkyl, heteroaryl alkyl, alkaryl or alkylheteroaryl, each optionally having substituent, preferably phenyl substituted by groups of formulae (I,II).The conducting or semiconducting segment is preferably chosen from poly(thiophene), poly(acetylene), poly(aniline), poly(pyrrole), poly(phenylene), poly(phenylene vinylene), poly(fluorene) and poly(acene). Each position of the conducting or semiconducting segment available for substitution is optionally substituted. The polymer segment comprises a homo-polymer. The conducting or semiconducting segment has 4 or more, preferably 10 or more structural repeating units. The conducting or semiconducting segment is a terminal segment of the macro-RAFT agent. Preferred Agent: The macro-RAFT agent is of formula: Q'(-L'-S-C(=S)-Z')m or Q'L'-S-C(=S)-S-L'-Q'. The cleaving agent is a nucleophilic species or radical species. EXAMPLE - 4-(Butyl thiocarbonothioylthio)-4-cyano pentanoic acid (in g) (0.53) and dicyclohexylcarbodiimide (0.41) were dissolved in dichloromethane (10 ml). The mixture was stirred for 15 minutes, and the solution of (4,3"'-dimethyl(5,2':5',2":5",2"'-quaterthiophene)-2-yl)methanol (0.64) and dimethylaminopyridine (8 mg) in dichloromethane (10 ml) was added. The solution was precipitated, filtered and washed. The filtrate was concentrated and purified to produce (4,3"'-dimethyl(5,2':5',2":5",2"'-quaterthiophene)-2-yl)methyl-4-(butylthiocarbonothioylthio)-4-cyanopentanoate.