TECHNOLOGY FOCUS - POLYMERS - Preparation (disclosed): The compound (M) is prepared by coupling reaction of donor structural unit-containing compound of formula: M1-(S2)m2-(D')l-(S1)m1-M2 (IV) and acceptor structural unit-containing compound of formula: M3-(A)n-M4 (V).M1,M2=trialkyltin, trialkylsilyl, or -B(OR'a)2;M3,M4=halo or perfluoroalkyl sulfonyloxy;andR'a=H or alkyl.Preferred Property: The compound (M) has a weight average molecular weight of 5000 to 1 million. Preferred Composition: The compound (M) is preferably chosen from formulae (VI)-(X). The carbon number of alkyl group, alkenyl group, or alkynyl group contained in the donor structural unit of compound (M) is 6-24. The semiconductor layer has a mixed layer containing compound (M) and n-type semiconductor.X131-X134,X141-X144,X151-X153,X161-X163,X171,X172=S, O, or -NR22-;Y131,Y132,Y141-Y145,Y151,Y161-Y165,Y171-Y173=N or -C(-L22-R23)=;L131-L133,L141,L142,L151,L152,L161,L163,L171,L172=single bond, -O-, -S-, -NR5-, -Si(R5)2-, -C(=O)O-, -C(=S)O-, -C(=O)S-, -SC(=O)-, -OC(=O)-, -OC(=S)-, -C(=O)-, -C(=S)-, -C(=O)NR5-, -NR5C(=O)-, -S(=O)-, -S(=O)2-, -S(=O)2O-, -OS(=O)2-, -S(=O)2NR5-, -NR5S(=O)2-, arylenyl, heteroarylenyl, alkenylenyl, alkynylenyl, or group which bonds with arylenyl, heteroarylenyl, alkenylenyl, alkynylenyl, carbonyl, or acyloxy;R131-R133,R141,R142,R151,R152,R62-R66,R161,R163,R171,R172=H or monovalent substituent;W151,W171=-NR62-, -CR63R64- or -C=CR65R66;andZ151,Z152=O or S. EXAMPLE - 190 mg (2-Cyclododecyl-6-(trimethylstannyl)thieno(3,4-b)thiophen-4-yl)trimethylstannane, 159 mg 4,6-dibromo-2-(cyclododecanesulfonyl)thieno(3,4-d)(1,3)thiazole, 6.21 mg tris(dibenzylideneacetone)dipalladium(0), and 14.6 mg o-tolylphosphine were added to a reaction container, to obtain a mixture. 6 mL Chlorobenzene was added to the obtained mixture, and the mixture was reacted at 140 degrees C in argon atmosphere for 12 hours. The mixture was cooled by adding methanol and the reaction solution was crystallized. The resultant solution was extracted using chlorobenzene and filtered, to separate solids. The separated solids were dried, to obtain donor acceptor structural unit-containing compound of formula (XI), with yield of 80%.