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 -(U) b -(Ar 2 ) c -(Ar 3 ) d ] n -* IVd *-([(Ar 1 ) a -(U) 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(O)NR 0 R 00 ,-C(O)X 0 , -C(O)R 0 , -C(O)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 -(U) 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(O)NR 0 R 00 ,-C(O)X 0 , -C(O)R 0 , -C(O)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, <EOS>