Polymer containing 0.1 to 50 mol% of at least one structural unit of the general formula I, where Z is an aromatic or heteroaromatic ring system having 5 to 60 ring atoms, selected from indenofluorene, which may be substituted by one or more radicals R, X is selected from a direct bond, a linear or branched alkylene group having 1 to 20 C atoms, in which one or more non-adjacent CH 2 groups may be replaced by -O-, -S-, -NH-, -N(CH 3)-, -N-CO-, -N-CO-O-, -N-CO-N, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CH(halogen)-, -CH -, -CH=CH- or -C≡C-, or a cyclic alkyl group, Ar 1, Ar 2 are each, independently of one another, an aryl or heteroaryl group having 5 to 60 ring atoms, which may be substituted by one or more radicals R of any desired type or may be linked to one another, where Ar 1 is a 1,4-linked aryl or heteroaryl group, Q is a crosslinkable group selected from a vinyl or alkenyl group, R is selected on each occurrence, independently of one another, from F, Cl, Br, I, N(Ar) 2, N(R 2) 2, CN, NO 2, Si(R 2) 3, B(OR 2) 2, C(=O)Ar, C(=O)R 2, P(=O)(Ar) 2, P(=O)(R 2) 2, S(=O)Ar, S(=O)R 2, S(=O) 2 Ar, S(=O) 2 R 2, -CR 2 =CR 2 Ar, OSO 2 R 2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, which may in each case be substituted by one or more radicals R 2, where one or more non-adjacent CH 2 groups may be replaced by R 2 C=CR 2, C≡C, Si(R 2) 2, Ge(R 2) 2, Sn(R 2) 2, C=O, C=S, C=Se, C=NR 2, P(=O)(R 2), SO, SO 2, NR 2, O, S or CONR 2 and where one or more H atoms may be replaced by F, Cl, Br, I, CN or NO 2, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2, or a combination of these systems, where two or more substituents R may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another, where R 2 is in each case, independently of one another, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms, R 1 is a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms or a silyl group or substituted keto group having 1 to 40 C atoms, or a substituted or unsubstituted aromatic or heteroaromatic ring system having 5 to 60 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 60 ring atoms, or a combination of these systems, or Ar 2, where one or more H atoms may be replaced by fluorine, n is 1, 2, 3 or 4, and the dashed lines represent the linking in the polymer, where, if n = 1, X is not a direct bond. Z is an aromatic or heteroaromatic ring system having 5 to 60 ring atoms, selected from indenofluorene, which may be substituted by one or more radicals R, X is selected from a direct bond, a linear or branched alkylene group having 1 to 20 C atoms, in which one or more non-adjacent CH 2 groups may be replaced by -O-, -S-, -NH-, -N(CH 3)-, -N-CO-, -N-CO-O-, -N-CO-N, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CH(halogen)-, -CH -, -CH=CH- or -C≡C-, or a cyclic alkyl group, Ar 1, Ar 2 are each, independently of one another, an aryl or heteroaryl group having 5 to 60 ring atoms, which may be substituted by one or more radicals R of any desired type or may be linked to one another, where Ar 1 is a 1,4-linked aryl or heteroaryl group, Q is a crosslinkable group selected from a vinyl or alkenyl group, R is selected on each occurrence, independently of one another, from F, Cl, Br, I, N(Ar) 2, N(R 2) 2, CN, NO 2, Si(R 2) 3, B(OR 2) 2, C(=O)Ar, C(=O)R 2, P(=O)(Ar) 2, P(=O)(R 2) 2, S(=O)Ar, S(=O)R 2, S(=O) 2 Ar, S(=O) 2 R 2, -CR 2 =CR 2 Ar, OSO 2 R 2, a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, which may in each case be substituted by one or more radicals R 2, where one or more non-adjacent CH 2 groups may be replaced by R 2 C=CR 2, C≡C, Si(R 2) 2, Ge(R 2) 2, Sn(R 2) 2, C=O, C=S, C=Se, C=NR 2, P(=O)(R 2), SO, SO 2, NR 2, O, S or CONR 2 and where one or more H atoms may be replaced by F, Cl, Br, I, CN or NO 2, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2, or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2, or a combination of these systems, where two or more substituents R may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another, where R 2 is in each case, independently of one another, H or an aliphatic or aromatic hydrocarbon radical having 1 to 20 C atoms, R 1 is a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkoxy group having 3 to 40 C atoms or a silyl group or substituted keto group having 1 to 40 C atoms, or a substituted or unsubstituted aromatic or heteroaromatic ring system having 5 to 60 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 60 ring atoms, or a combination of these systems, or Ar 2, where one or more H atoms may be replaced by fluorine, n is 1, 2, 3 or 4, and