TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): Conjugated phenylene polymer is prepared by subjecting monomer(s) (II) and optionally monomer(s) of formula R7-Ar1-R8 and/or R7-Ar2-R8, to an aryl-aryl coupling reaction. Preferred Compound: The conjugated phenylene polymer is of formula (Ia), (Ib), -(MU)n- (Ia1), or R5-(MU)n-R6 (Ib1).n=greater than 1;R5, R6=R1, H, halo, -CH2Cl, -CHO, -CH=CH2, -SiR'R''R''', -SnR'R''R''', -BR'R'', -B(OR')(OR''), -B'(OH)2, or P'-Sp;R', R'', R'''=R0;andMU=monomeric repeating unit selected from one or more of 32 compounds, e.g. (I1)-(I3).The conjugated phenylene polymer comprises repeating unit(s) selected from one or more of 32 compounds, e.g. compounds (I1)-(I3).Ar'=Ar1.Monomer (II) is R7-MU-R8 (II1). Preferred Definitions:    R1-R4=straight- or branched-chain, 1-20C alkyl, 1-20C alkoxy, 2-20C alkenyl, 2-20C alkynyl, 1-20C thioalkyl, 1-20C silyl, 1-20C ester, 1-20C amino, 1-20C fluoroalkyl;and    Ar1, Ar2=2,1,3-benzothiadiazole-4,7-diyl, 2,1,3-benzoselenadiazole-4,7-diyl, 2,3-dicyano-1,4-phenylene, 2,5-dicyano, 1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,3,5,6-tetrafluoro, 1,4-phenylene, 3,4-difluorothiophene-2,5-diyl, thieno(3,4-b)pyrazine-2,5-diyl, quinoxaline-5,8-diyl, 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, 1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, p-p'-biphenyl, naphthalene-2,6-diyl, benzo(1,2-b:4,5-b')dithiophene-2,6-diyl, 2,2-dithiophene, 2,2-diselenophene, thiazole, or oxazole, all of which are unsubstituted, mono-, or polysubstituted with R1.    EXAMPLE - In a dried flask, 2,7-dibromo-5,5,10,10-tetra-2'-ethylhexylbenzo(1",2":4,5;4",5":4',5')-bis(silolo(3,2-b:3',2'-b')thiophene) (200.0 mg), 4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,1,3-benzothiadiazole (85.8 mg), tris(dibenzylideneacetone)dipalladium(0) (4.0 mg) and tri(o-tolyl)phosphine (5.4 mg) were dissolved in degassed toluene (5.0 cm3) and degassed 2 M aqueous sodium carbonate (0.5 cm3). The reaction mixture was vigorously stirred at 100-105 degrees C for 24 hours. The polymer was purified by precipitation into methanol:water (10:1), filtered, and washed sequentially via Soxhlet extraction with acetone, petroleum ether, and chloroform. The acetone and chloroform fractions were reduced to a smaller volume under reduced pressure and precipitated into methanol. The precipitated polymer was filtered and dried under vacuum at 25 degrees C overnight to afford poly(2,7-(5,5,10,10-tetra-2'-ethylhexylbenzo(1",2":4,5;4",5":4',5')-bis(silolo(3,2-b:3',2'-b')thiophene))-alt-4,7-(2,1,3-benzothiadiazole)) (acetone fraction: 99 mg, yield 51%; chloroform fraction: 12 mg, yield 6%).