TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): The monomer (M) is coupled with each other and/or with monomer of formula: R2-Ar-R3 by aryl-aryl coupling reaction, and conjugated polymer is produced. Preferred Polymer: The polymer further has repeating unit of formula: -(((Ar)y-(A)x)m)n-. The polymer is of formula: R2-(((Ar)y-(A)x)m)n-R3.Ar=optionally substituted aryl or heteroaryl, preferably chosen from selenophene-2,5-diyl, thiophene-2,5-diyl, thieno(3,2-b)thiophene-2,5-diyl, thieno(2,3-b)thiophene-2,5-diyl, selenopheno(3,2-b)selenophene-2,5-diyl, selenopheno(2,3-b)selenophene-2,5-diyl, selenopheno(3,2-b)thiophene-2,5-diyl, selenopheno(2,3-b)thiophene-2,5-diyl, benzo(1,2-b:4,5- b')dithiophene-2,6-diyl, 2,2-dithiophene, 2,2-diselenophene, 4H-cyclopenta(2,1-b:3,4-b')dithiophene-2,6-diyl, 2,7-di-thien-2-yl-carbazole, 2,7-di-thien-2-yl-fluorene, indaceno(1,2-b:5,6-b')dithiophene-2,7-diyl, benzo(1",2":4,5:4",5":4',5')bis(silyl(3,2-b:3',2'-b')thiophene)-2,7-diyl, 2,7-di-thien-2-yl-indaceno(1,2-b:5,6-b')dithiophene, 2,7-di-thien-2-yl-benzo(1",2":4,5:4",5":4',5')bis(silyl(3,2-b:3',2'-b,)thiophene)-2,7-diyl, 2,7-di-thien-2-yl-phenanthro(1,10,9,8-c,d,e,f,g)carbazole, 4,7-di-thien-2-yl-benzo(1,2,3)thiadiazole, 4,7-di-thien-2-yl-benzo(1,2,3)selenadiazole, 3,4-difluorothiophene-2,5-diyl, 2,5-di-thien-2-yl-thieno(3,4-b)pyrazine, 5,8-di-thien-2-yl-quinoxaline, thieno(3,4-b)thiophene-4,6-diyl, 4,6-di-thien-2-yl-thieno(3,4-b)thiophene, thieno(3,4-b)thiophene-6,4-diyl, 6,4-di-thien-2-yl-thieno(3,4-b)thiophene, 3,6-di-thien-2-yl-pyrrolo(3,4-c)pyrrole-1,4- dione;Y1,Y2=H, fluoro, chloro or cyano;m=1-3;x,y=0 or 1;n=more than 1;R2,R3=H, -CH2Cl, -CHO, -CH=CH2, -SiR4R5R6 - SnR4R5R6, -B(OR4)(OR5), -B(OH)2, or P'-Sp;R4-R6=R';andR4+R5=ring.N.B: Y1 and Y2 are defined but do not appear in structure. Preferred Definitions:    X1,X3=sulfur;    X2,X4=CH;    R=-CO-R7 or -COO-R7;and    R7=1-30C primary alkyl, 3-30C secondary alkyl or 4-30C tertiary alkyl, in which H is optionally substituted by fluoro.    EXAMPLE - A solution of 4,8-dibromo-benzo(1,2-b:4,5-b')dithiophene-2,6-dicarboxylic acid bis-(2-ethyl-hexyl) ester (in mg) (198), 2,5-bis- trimethylstannyl-thiophene (246), 4,7-dibromo-5,6-bis-octyloxy-benzo(1 ,2,5)thiadiazole (165), tri(o-tolyl)phosphine (15) and tris(dibenzylideneacetone)dipalladium(O) (11) was prepared. The mixture was purged with nitrogen for 5 minutes. The reaction mixture was placed in a microwave reactor and heated at 140 degrees C, 160 degrees C, 170 degrees C and 180 degrees C sequentially. The reaction mixture was cooled and precipitated. The mixture was stirred for 10 minutes. The polymer was collected by filtration and washed with methanol. The crude polymer was washed with acetone and cyclohexane. The cyclohexane extract was precipitated, filtered and dried under vacuum to produce poly(4,7-5,6-bis-octyloxy-benzo(1,2,5)thiadiazole)-co-(2,5-thienyl)-co-(4,8-benzo(1,2-b:4,5-b')dithiophene-2,6-dicarboxylic acid bis-(2-ethyl-hexyl) ester) having number average molecular weight of 6700 g/mol, and weight average molecular weight of 10500 g/mol.