Compound of the formula or formula, where the following applies to the symbols used: X is on each occurrence, identically or differently, CR or N or two adjacent X stand for a group of the following formula, where ^ indicates the corresponding adjacent groups X in the formula or formula; with the proviso that the compound of the formula or formula contains at least one group of the formula; Z is on each occurrence, identically or differently, CR or N; L is a single bond or a divalent group, where L is bonded instead of a group R or R 1; R is on each occurrence, identically or differently, selected from the group consisting of H, D, F, CI, Br, I, CN, NO 2, N(Ar 1) 2, N(R 2) 2, C(=O)Ar 1, C(=O)R 2, P(=O)(Ar 1) 2, P(Ar 1) 2, B(Ar 1) 2, Si(Ar 1) 3, Si(R 2) 3, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 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, C=O, C=S, 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 D, F, CI, Br, I, CN or NO 2, 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, an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2; two adjacent substituents R here may optionally form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R 2; R 1 is on each occurrence, identically or differently, selected from the group consisting of 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; Ar 1 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5-30 aromatic ring atoms, which may be substituted by one or more non-aromatic radicals R 2; two radicals Ar 1 here which are bonded to the same N atom or P atom may also be bridged to one another by a single bond or a bridge selected from N(R 2), C(R 2) 2, O or S; R 2 is on each occurrence, identically or differently, selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms may be replaced by D, F, CI, Br, I or CN, where two or more adjacent substituents R 2 may form a mono- or polycyclic, aliphatic ring system with one another. X is on each occurrence, identically or differently, CR or N or two adjacent X stand for a group of the following formula, where ^ indicates the corresponding adjacent groups X in the formula or formula; with the proviso that the compound of the formula or formula contains at least one group of the formula; Z is on each occurrence, identically or differently, CR or N; L is a single bond or a divalent group, where L is bonded instead of a group R or R 1; R is on each occurrence, identically or differently, selected from the group consisting of H, D, F, CI, Br, I, CN, NO 2, N(Ar 1) 2, N(R 2) 2, C(=O)Ar 1, C(=O)R 2, P(=O)(Ar 1) 2, P(Ar 1) 2, B(Ar 1) 2, Si(Ar 1) 3, Si(R 2) 3, a straight-chain alkyl, alkoxy or thioalkyl group having 1 to 40 C atoms or a branched or cyclic alkyl, alkoxy or thioalkyl group having 3 to 40 C atoms or an alkenyl or alkynyl group having 2 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, C=O, C=S, 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 D, F, CI, Br, I, CN or NO 2, 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, an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R 2; two adjacent substituents R here may optionally form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system, which may be substituted by one or more radicals R 2; R 1 is on each occurrence, identically or differently, selected from the group consisting of 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; Ar 1 is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5-30 aromatic ring atoms, which may be substituted by one or more non-aromatic radicals R 2; two radicals Ar 1 here which are bonded to the same N atom or P atom may also be bridged to one another by a single bond or a bridge selected from N(R 2), C(R 2) 2, O or S; R 2 is on each occurrence, identically or differently, selected from the group consisting of H, D, F, CN, an aliphatic hydrocarbon radical having 1 to 20 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, in which one or more H atoms may be replaced by D, F, CI, Br, I or CN, where two or more adjacent substituents R 2 may form a mono- or polycyclic, aliphatic ring system with one another.