A conjugated polymer selected from the following formulae *-[(A r 1 -U-Ar 2) x -(Ar 3) y] n -* IVa *-[(Ar 1 -U-Ar 2) x -(Ar 3 -Ar 3) y] n -* IVb *-[(Ar 1 -U-Ar 2) x -(Ar 3 -Ar 3 -Ar 3) y] n -* IVc *-[(Ar 1) a - b -(Ar 2) c -(Ar 3) d] n -* IVd *-([(Ar 1) a - b -(Ar 2) c -(Ar 3) d] x -[(Ar 1) a -(A c) b -(Ar 2) c -(Ar 3) d] y) n -* IVe wherein U is a unit of formula I wherein X 1 and X 2 independently of each other denote C(R 1 R 2), A 1 and A 2 are selected from the group consisting of the formulae 2a, 3a, 3b and 7a, R 1 and R 2 are independently of each selected from the group consisting of the following formulae wherein "ALK" denotes optionally fluorinated, preferably linear, alkyl or alkoxy with 1 to 20 C-atoms, and the dashed line denotes the link to the ring to which these groups are attached R 0 and R 00 are independently of each other H or alkyl with 1 to 12 C-atoms Ar 1, Ar 2, Ar 3 are, on each occurrence identically or differently, and independently of each other, aryl or heteroaryl that is different from U, preferably has 5 to 30 ring atoms, and is optionally substituted, preferably by one or more groups R S, A c is an aryl or heteroaryl group that is different from U and Ar 1-3, has 5 to 30 ring atoms, is optionally substituted by one or more groups R S, and is preferably selected from aryl or heteroaryl groups having electron acceptor properties, R S is on each occurrence identically or differently F, Br, Cl,-CN, -NC, -NCO, -NCS, -OCN, -SCN, -C NR 0 R 00,-C X 0, -C R 0, -C OR 0, -NH 2, -NR 0 R 00, -SH, -SR 0,-SO 3 H, -SO 2 R 0, -OH, -NO 2, -CF 3, -SF 5, optionally substituted silyl, carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X 0 is F, Cl or Br, a, b and c are on each occurrence identically or differently 0, 1 or 2, d is on each occurrence identically or differently 0 or an integer from 1 to 10, x is > 0 and ≤ 1, y is ≥ 0 and < 1, x + y is 1, and n is an integer >10, wherein these polymers can be alternating or random copolymers, and wherein in formula IVd and IVe in at least one of the repeating units [(Ar 1) a - b -(Ar 2) c -(Ar 3) d] and in at least one of the repeating units [(Ar 1) a -(A c) b -(Ar 2) c -(Ar 3) d] b is at least 1. X 1 and X 2 independently of each other denote C(R 1 R 2), A 1 and A 2 are selected from the group consisting of the formulae 2a, 3a, 3b and 7a, R 1 and R 2 are independently of each selected from the group consisting of the following formulae R 0 and R 00 are independently of each other H or alkyl with 1 to 12 C-atoms Ar 1, Ar 2, Ar 3 are, on each occurrence identically or differently, and independently of each other, aryl or heteroaryl that is different from U, preferably has 5 to 30 ring atoms, and is optionally substituted, preferably by one or more groups R S, A c is an aryl or heteroaryl group that is different from U and Ar 1-3, has 5 to 30 ring atoms, is optionally substituted by one or more groups R S, and is preferably selected from aryl or heteroaryl groups having electron acceptor properties, R S is on each occurrence identically or differently F, Br, Cl,-CN, -NC, -NCO, -NCS, -OCN, -SCN, -C NR 0 R 00,-C X 0, -C R 0, -C OR 0, -NH 2, -NR 0 R 00, -SH, -SR 0,-SO 3 H, -SO 2 R 0, -OH, -NO 2, -CF 3, -SF 5, optionally substituted silyl, carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X 0 is F, Cl or Br, a, b and c are on each occurrence identically or differently 0, 1 or 2, d is on each occurrence identically or differently 0 or an integer from 1 to 10, x is > 0 and ≤ 1, y is ≥ 0 and < 1, x + y is 1, and n is an integer >10,