TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The organic layer is: a hole transport layer (103), a hole injection layer or simultaneously a layer of hole transport and hole injection functions including the copolymer; or an electron injection layer, an electron transport layer or simultaneously a layer of an electron injection and electron transport functions including the copolymer. The photoactive layer is electron donor and at least one an electron acceptor, where the electron donor includes the copolymer. The electron acceptor is fullerene, fullerene derivatives, carbon nanotubes, carbon nanotube derivatives, basocuproin, semiconducting element and/or semiconducting compounds. The electron donor and the electron acceptor are constitutes a bulk heterojunction (BHJ). The photoactive layer is bi-layer thin film structure comprising a n-type organic layer and a p-type organic layer, where the p-type organic layer comprises copolymer.    TECHNOLOGY FOCUS - POLYMERS - Preparation: No preparation method is given. Preferred Components: The copolymer is of formula (-((B1-A-)x(B'-C1-)y))n) (IV). The copolymer is a random copolymer. The number average molecular weight of the copolymer is 500-1000000 g/mol. The molecular weight distribution of the copolymer is 1-100.A = (I);B1, B' = (II);C1 = (III);x, y = 0-1;x+y = 1; andn = 1-10000. EXAMPLE - 0.600 g 2,6-Bis(trimethyltin)-4,8-di (2-ethylhexyloxybenzo(1,2-b:4,5-b')dithiophene, 0.3213 g (4,7-bis(5-bromothiophene-2-yl)-5,6-bis(dodoecyloxy)-benzo(c)(1,2,5)-thiadiazole, 0.1861 g 1,3-dibromo-5-dodecylthieno(3,4-c)pyrrole-4,6-dione, 10 mg tris(dibenzylideneacetone)dipalladium(0) and 80 mg tri-(o-tolyl)phosphine were dissolved in 12 ml chlorobenzene and reacted for 1 hour at 170 degrees C. The reaction mixture was cooled, solvent was removed and poured in to acetone, extracted with hexane and chloroform mixture, the chloroform portion was re-precipitated in methanol to obtain solid 4-(5-(4,8-bis-(2-ethyl-hexyloxy)-6-methyl-benzo(1,2-b;4,5-b')dithiophen-2-yl)-thiophen-2-yl)-5,6-bis-dodecyloxy-7-thiophen-2-yl-benzo(1,2,5)thiadiazole-3-(4,8-bis-(2-ethyl-hexyloxy)-benzo(1,2-b;4,5-b')dithiophen-2-yl)-5-dodecyl-1-methyl-thieno(3,4-c)pyrrole-4,6-dione copolymer of formula (V) having weight average molecular weight of 49826 g/mol (54% yield).