TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Preparation of polymer comprising (repeating) units of formula (-(COM1)-) (II) comprises: reacting a dihalo compound of formula (X10-A-X10) (a1) with an equimolar amount of a diboronic acid or diboronate compound of formula (X11-(COM1)-X11); or reacting a dihalo compound of formula (X10-(COM1)-X10) (b1) with an equimolar amount of a diboronic acid or diboronate compound of formula (X11-A-X11) in a solvent and in the presence of a catalyst; or reacting a dihalo compound (a1) with an equimolar amount of an organo tin compound of formula (X11a-(COM1)-X11a); or reacting a dihalo compound (b1) with an equimolar amount of an organo tin compound of formula (X11a-A-X11a).X10 = halo, preferably Br;X11 = -B(OH)2, -B(OY1)2, (1a) or (2a);COM1 = repeating unit comprising Ar1 e.g. thieno(3,2-b)thiophenyl group of formula (i), thieno(2,3-b)thiophene group of formula (j), phenyl group of formula (k), naphthyl group of formula (l) or (m), 9H-carbazolyl group of formula (n), 9H-fluorene group of formula (o), (2,2')bithiophenyl group of formula (p), heteroaryl group of formula (q), (2,2')bithiazolyl group of formula (r) or (5,5')bithiazolyl group of formula (s); andX11a = -SnR207R208R209.Preferred Components: (A) comprises (repeating) unit(s) of formula (-(A)-) or (II).A = repeating unit (I). Full Definitions:    a = 1-3;    a1, b, b1, c, c1, d, d1 = 0-3, with the proviso that b1 is not 0, if a1 is 0;    R1, R2 = H, 1-100C alkyl (optionally substituted by one or more halo, OH, nitro, CN or 6-18C aryl groups and/or interrupted by -O-, -COO-, -OCO- or -S-), -COOR103, 7-100C arylalkyl (optionally substituted 1-3 times with 1-8C alkyl and/or 1-8C alkoxy), carbamoyl, 5-12C cycloalkyl (optionally substituted 1-3 times with 1-8C alkyl and/or 1-8C alkoxy), 6-24C aryl, in particular phenyl or 1- or 2-naphthyl (optionally substituted 1-3 times with 1-8C alkyl, 1-8C thioalkoxy, and/or 1-8C alkoxy) or pentafluorophenyl;    Ar1, Ar1a = an annulated (aromatic) heterocyclic ring system, containing at least one thiophene ring (optionally substituted by one, or more groups), preferably e.g. thieno(3,2-b)thiophenyl, thieno(2,3-b)thiophenyl, dithieno(3,2-b;2',3'-d)thiophenyl, 4H-cyclopenta(2,1-b;3,4-b')dithiophenyl, 4H-indeno(1,2-b)thiophenyl, 2,3-dihydro-benzo(1,2-b;4,5-b')dithiophenyl, benzo(b)thiophenyl, 4H-dithieno(3,2-b;2',3'-d)pyrrolyl, 1,2,3a,7a-tetrahydro-7-oxa-3,4-dithia-cyclopenta(a)pentalenyl, 7H-3,4-dithia-7-sila-cyclopenta(a)pentalenyl, dibenzothiophenyl, 5,10-dithia-indeno(2,1-a)indenyl, 4H-thieno(3,2-b)pyrrolyl, 6H-thieno(2,3-b)pyrrolyl, 2,6,7-trithia-1,3-diaza-trindenyl, 3,4,7,8-tetrathia-dicyclopenta(a,e)pentalenyl, 1H,3H-6,7-dithia-1,3-diaza-trinden-2-one or benzo(b)thieno(2,3-d)thiophenyl (all optionally substituted);    Ar2, Ar2a, Ar3, Ar3a, Ar4, Ar4a = Ar1, thiophenyl groups of formula (a) or (b), phenyl group of formula (c), naphthyl groups of formula (d) or (e), 9H-carbazolyl group of formula (f), 9H-fluorenyl group of formula (h), benzo(1,2,5)thiadiazol-4,7-diyl or 2,3-dihydro-thieno(3,4-b)(1,4)dioxin-5,7-diyl;    one of X3, X4 = N and the other is CR99;    R99, R104, R104a = H, halo (preferably F) or 1-25C alkyl, preferably 4-25C alkyl (optionally be interrupted by one or more O or S), 7-25C arylalkyl or 1-25C alkoxy;    R105, R105a, R106, R106a = H, halo, 1-25C alkyl (optionally be interrupted by one or more O or S), 7-25C arylalkyl or 1-18C alkoxy;    R107 = 7-25C arylalkyl, 6-18C aryl (optionally substituted by C1-18C alkyl, 1-18C perfluoroalkyl or 1-18C alkoxy), 1-18C alkyl (optionally interrupted by -O- or -S-) or -COOR103;    R103 = 1-50C alkyl, preferably 4-25C alkyl; either    R108, R109 = H, 1-25C alkyl (optionally substituted by E and/or interrupted by D), 7-25C arylalkyl, 6-24C aryl (optionally substituted by G), 2-20C heteroaryl (optionally substituted by G), 2-18C alkenyl, 2-18C alkynyl, 1-18C alkoxy (optionally substituted by E and/or interrupted by D) or 7-25C aralkyl; or    R108R109 = =CR110R111; or    R108R109 = 5 or 6 membered ring (optionally substituted by 1-18C alkyl (optionally substituted by E and/or interrupted by D), 6-24C aryl (optionally substituted by G), 2-20C heteroaryl (optionally substituted by G), 2-18C alkenyl, 2-18C alkynyl, 1-18C alkoxy (optionally substituted by E and/or interrupted by D) or 7-25C aralkyl);    R110, R111 = H, 1-18C alkyl (optionally substituted by E and/or interrupted by D), 6-24C aryl (optionally substituted by G) or 2-20C heteroaryl (optionally substituted by G);    D = -CO-, -COO-, -S-, -O- or -NR112-;    E = 1-8C thioalkoxy, 1-8C alkoxy, CN, -NR112R113, -CONR112R113 or halo;    G = E or 1-18C alkyl; and    R112, R113 = H, 6-18C aryl (optionally substituted by 1-18C alkyl or 1-18C alkoxy) or 1-18C alkyl (optionally interrupted by -O-).    EXAMPLE - 3,6-Bis-(5-bromo-thieno(3,2-b)thiophen-2-yl)-2,5-bis-(2-decyl-tetradecyl)-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione (810 mg), thiophene-di-boronic acid pinacol ester (208 mg), tris(dibenzylideneacetone)-di-palladium (15 mg) and tri-tert-butylphosphonium-tetrafluoroborate (10 mg) were dissolved in tetrahydrofuran (4 ml). This solution was degassed with 3 cycles of freeze/pump/thaw. The reaction mixture was then heated to reflux temperature. Then potassium phosphate (418 mg) was dissolved in water (1.2 ml) and degassed under argon. The water solution was added to the tetrahydrofuran solution and the reaction mixture was refluxed over night. Then 2-thiophene-mono-boronic-acid-pinacol-ester (14 mg) was added, and the mixture was refluxed for another 30 minutes. Then 2-bromothiophene (11 mg) was added, and the mixture was refluxed for another 30 minutes. The reaction mixture was cooled to room temperature and diluted with water and then extracted with chloroform. The chloroform solution was then refluxed with a solution of sodium cyanide in water for 1 hour. The water was separated and the chloroform solution dried. The residue was then extracted with tetrahydrofuran. The organic phase was precipitated to give polymer comprising 2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione repeating unit of formula (Ia) (635 mg, having molecular weight of 38000, and polydispersity of 2.78).