Polymers containing at least 1 mol% of a first recurring unit of the formula, where the symbols and indices used have the following meaning: R is on each occurence, identically or differently, H, a straight-chain alkyl chain having 1 to 40 C atoms or a branched or cyclic alkyl chain having 3 to 40 C atoms, each of which may be substituted by R 1 and in which, in addition, one or more non-adjacent C atoms may be replaced by N-R 1, O, S, O-CO-O, CO-O, -CR 1 =CR 1 - or -C≡C-, with the proviso that the heteroatoms are not bonded directly to the naphthyl unit, and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may also be substituted by one or more radicals R 1; the two radicals R here may also form a further ring system with one another; with the proviso that at least one of the two radicals R is not equal to H; X is on each occurence, identically or differently, -CR 1 =CR 1 -, -C≡C- or N-Ar; Y is on each occurence, identically or differently, a divalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more radicals R 1 or unsubstituted; R 1 is on each occurence, identically or differently, H, F, Cl, Br, I, CN, N(R 2) 2, Si(R 2) 3, B(R 2) 2, a straight-chain alkyl or alkoxy chain having 1 to 40 C atoms or a branched or cyclic alkyl or alkoxy chain having 3 to 40 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by N-R 2, O, S, O-CO-O, CO-O, -CR 1 =CR 1 - or -C≡C- and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, or an aryl, aryloxy or heteroaryl group having 5 to 40 aromatic ring atoms, which may also be substituted by one or more non-aromatic radicals R 1; two or more of the radicals R 1 here may also form a ring system with one another; R 2 is on each occurence, identically or differently, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms; Ar is on each occurence, identically or differently, a monovalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by R 1 or unsubstituted; n is on each occurence, identically or differently, 0 or 1; m is on each occurence, identically or differently, 0, 1, 2, 3 or 4; o is on each occurence, identically or differently, 0, 1 or 2; p is on each occurence, identically or differently, 0 or 1; the dashed bond here denotes the linking in the polymer; and additionally containing at least 1 mol% of a second recurring unit, which is either identical to or different from a recurring unit of the formula. R is on each occurence, identically or differently, H, a straight-chain alkyl chain having 1 to 40 C atoms or a branched or cyclic alkyl chain having 3 to 40 C atoms, each of which may be substituted by R 1 and in which, in addition, one or more non-adjacent C atoms may be replaced by N-R 1, O, S, O-CO-O, CO-O, -CR 1 =CR 1 - or -C≡C-, with the proviso that the heteroatoms are not bonded directly to the naphthyl unit, and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, or an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may also be substituted by one or more radicals R 1; the two radicals R here may also form a further ring system with one another; with the proviso that at least one of the two radicals R is not equal to H; X is on each occurence, identically or differently, -CR 1 =CR 1 -, -C≡C- or N-Ar; Y is on each occurence, identically or differently, a divalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by one or more radicals R 1 or unsubstituted; R 1 is on each occurence, identically or differently, H, F, Cl, Br, I, CN, N(R 2) 2, Si(R 2) 3, B(R 2) 2, a straight-chain alkyl or alkoxy chain having 1 to 40 C atoms or a branched or cyclic alkyl or alkoxy chain having 3 to 40 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by N-R 2, O, S, O-CO-O, CO-O, -CR 1 =CR 1 - or -C≡C- and in which, in addition, one or more H atoms may be replaced by F, Cl, Br, I or CN, or an aryl, aryloxy or heteroaryl group having 5 to 40 aromatic ring atoms, which may also be substituted by one or more non-aromatic radicals R 1; two or more of the radicals R 1 here may also form a ring system with one another; R 2 is on each occurence, identically or differently, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms; Ar is on each occurence, identically or differently, a monovalent aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may be substituted by R 1 or unsubstituted; n is on each occurence, identically or differently, 0 or 1; m is on each occurence, identically or differently, 0, 1, 2, 3 or 4; o is on each occurence, identically or differently, 0, 1 or 2; p is on each occurence, identically or differently, 0 or 1;