NOVELTY - Polymer comprising heterocyclic repeating units is new.    USE - The polymer is useful as organic semiconductor material, layer or component, which is useful in semiconductor device, preferably organic photovoltaic device (solar cell), a photodiode, or an organic field effect transistor (claimed).    ADVANTAGE - The polymer has: excellent solubility in organic solvents and excellent film-forming properties; and high efficiency of energy conversion, excellent field-effect mobility, good on/off current ratios and/or excellent stability.    DETAILED DESCRIPTION - Polymer comprising heterocyclic repeating units of formula (-(A)-), (-(COM1)-) and optionally (-(COM2)-), is new.    A = dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione repeating unit of formula (a);    a, b, c, d = 1-3;    a1, b1, c1, d1 = 0-3, provided that b1 is not 0, if a1 is 0;    R1, R2 = H, 1-100C alkyl group, -COOR103, 1-100C alkyl group (which is substituted by one or more halo, OH, nitro groups, -CN or 6-18C aryl groups and/or interrupted by -O-, -COO-, -OCO-, or -S-), 7-100C arylalkyl group, a carbamoyl group, 5-12C cycloalkyl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy), or 6-24C aryl group (preferably phenyl or 1- or 2-naphthyl which can be substituted one to three times with 1-8C alkyl, 1-8C thioalkoxy, and/or 1-8C alkoxy, or pentafluorophenyl);    R103 = 1-50C alkyl, preferably 4-25C alkyl;    Ar1, Ar11 = substituted phenyl group of formula (1a), heterocyclic group of formula (2a)-(5a), benzo(1,2,5)thiadiazol-4,7-diyl group or 2,3-dihydro-thieno(3,4-b)(1,4)dioxin-5,7-diyl group;    Ar2, Ar21, Ar3, Ar31, Ar4, Ar41 = naphthyl group of formula (6a) or (7a);    one of X3 and X4 = N and the other is CR99;    R99, R104, R104a = H, halo, preferably F, or 1-25C, preferably 4-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl or 1-25C alkoxy group;    R105, R105a = H, halo, 1-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl or 1-18C alkoxy;    R107 = H, 6-18C aryl (optionally substituted by 1-8C alkyl and/or 1-8C alkoxy), 1-18C alkyl (optionally interrupted by O);    -COM1- = heterocyclic repeating units of formula (8a) or (9a), preferably (10a);    -COM2- = a second repeating unit -COM1-, which is different from the first repeating unit -COM1-, a second repeating unit -A-, which is different from the first repeating unit -A- or benzo(1,2,5)thiadiazol-4,7-diyl group, 2,3-dihydro-thieno(3,4-b)(1,4)dioxin-5,7-diyl group, thiazolo(5,4-d)thiazol-2,5-diyl group or heterocyclic groups of formula (11a)-(17a);    one of X5 and X6 = N and the other is CR114;    R110 = 1-25C, 4-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl, 1-25C alkoxy group;    R111, R111a, R112, R112a = H, halo, preferably F, or 1-25C, preferably 4-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl, or 1-25C alkoxy;    R113 = 6-18C aryl (optionally substituted by 1-18C alkyl or 1-18C alkoxy), or 1-18C alkyl (optionally interrupted by -O-);    R114, R114a, R115, R115a = H or 1-25C, preferably 6-25C alkyl (optionally interrupted by one or more O);    p = 0-3;    r, s = 0 or 1;    one of R106 and R108 = H and the other is H, CN, 1-8C alkyl or COOR109;    R109 = 1-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl, or 6-24C aryl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy); either    R3, R3a, R4, R4a = H, halo, 1-25C alkyl (optionally interrupted by one or more O or S), 7-25C arylalkyl or 1-25C alkoxy; or    R4R4a = a ring;    X1, X2 = -O-, -S-, -NR8-, -Si(R11)(R11a)-, -C(R7)(R7a)-, C(=O)-, (1,2,5)thiadiazol-3,4-diyl, group of formula (-CR55=CR55a-), pyrazine group of formula (18a), dihydro-imidazolone group of formula (19a) or heterocyclic group of formula (20a);    X5 = -O- or -NR8-; either    R5, R5a = H, halo, 1-25C alkyl (optionally interrupted by one or more O or S), 6-24C aryl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy), 7-25C arylalkyl, CN or 1-25C alkoxy); or    R5R5a = a ring;    R55, R55a = H, F, 1-18C alkyl (interrupted by O), 1-18C alkoxy (interrupted by O), 1-18C perfluoroalkyl, 6-24C aryl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy), 2-20C heteroaryl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy);    R6 = H, 1-18C alkyl (optionally interrupted by one or more O or S), 1-18C perfluoroalkyl, 6-24C aryl(optionally substituted one to three times with 1-18C alkyl and/or 1-18C alkoxy), 2-20C heteroaryl (optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy) or CN;    R7, R7a = H, 1-35C alkyl (optionally interrupted by one or more O or S), or 7-25C arylalkyl;    R8, R8a = H, 6-18C aryl (substituted by 1-18C alkyl or 1-18C alkoxy), 1-25C, preferably 4-25C alkyl (optionally interrupted by one or more O or S) or 7-25C arylalkyl; and    R11, R11a = 1-35C alkyl, 7-25C arylalkyl or phenyl group (all optionally substituted one to three times with 1-8C alkyl and/or 1-8C alkoxy.    Provided that: (I) excludes polymer of formula (Q1) (where number average molecular weight (Mn) is 30 kg/mole and polydispersity is 2.1) or (Q2) (where number average molecular weight (Mn) is 22.7 kg/mole and polydispersity is 2.1); and if A is a diphenyl-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione group of formula (21a), then B is not fluorene group of formula (22a) or carbazole group of formula (23a).    R1a, R2a = H, 1-12C alkyl, 1-12C alkoxy, unsubstituted 6-12C aryl or one to three times with 1-12C alkyl, 1-12C alkoxy, or halogen substituted 6-12C aryl or perfluoro-1-12C alkyl; and    R3a = H or 1-18C alkyl.    INDEPENDENT CLAIMS are included for:    (1) an organic semiconductor material, layer or component, comprising the polymer;    (2) a semiconductor device, comprising the polymer, and/or an organic semiconductor material, layer or component; and    (3) preparing an organic semiconductor device, comprising applying a solution and/or dispersion of a polymer in an organic solvent to a substrate and removing the solvent.