Compound comprising at least one structure of the formula (I): where the following applies to the symbols used: X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 , X 11 , X 12 , X 13 , X 14 , X 15 , X 16 are CR 1 ; Ar is selected on each occurrence, identically or differently, from one of the formulae (R 1 -1) to (R 1 -95) where the following applies to the symbols used: Y is O, S or NR 2 , preferably O or S; i is on each occurrence, independently, 0, 1 or 2; j is on each occurrence, independently, 0, 1, 2 or 3; h is on each occurrence, independently, 0, 1, 2, 3 or 4; g is on each occurrence, independently, 0, 1, 2, 3, 4 or 5; and the dashed bond marks the bonding position; R 1 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, CN, N(Ar 1 ) 2 , a straight-chain alkyl group having 1 to 8 C atoms, or a branched or cyclic alkyl group having 3 to 8 C atoms, or an alkenyl group having 2 to 8 C atoms, which may in each case be substituted by one or more radicals R 2 , or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, which may in each case be substituted by one or more non-aromatic radicals R 1 ; Ar 1 is, identically or differently on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2 ; R 2 is selected on each occurrence, identically or differently, from the group consisting of H, D, an aliphatic hydrocarbon radical having 1 to 10 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may be substituted by one or more alkyl groups having in each case 1 to 4 carbon atoms; where in formula (I) at most 2 of the symbols X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 , X 11 , X 12 , X 13 , X 14 , X 15 , X 16 are not equal to CH or CD. X 1 , X 2 , X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 , X 11 , X 12 , X 13 , X 14 , X 15 , X 16 are CR 1 ; Ar is selected on each occurrence, identically or differently, from one of the formulae (R 1 -1) to (R 1 -95) Y is O, S or NR 2 , preferably O or S; i is on each occurrence, independently, 0, 1 or 2; j is on each occurrence, independently, 0, 1, 2 or 3; h is on each occurrence, independently, 0, 1, 2, 3 or 4; g is on each occurrence, independently, 0, 1, 2, 3, 4 or 5; and R 1 is selected on each occurrence, identically or differently, from the group consisting of H, D, F, CN, N(Ar 1 ) 2 , a straight-chain alkyl group having 1 to 8 C atoms, or a branched or cyclic alkyl group having 3 to 8 C atoms, or an alkenyl group having 2 to 8 C atoms, which may in each case be substituted by one or more radicals R 2 , or an aromatic or heteroaromatic ring system having 6 to 24 aromatic ring atoms, which may in each case be substituted by one or more non-aromatic radicals R 1 ; Ar 1 is, identically or differently on each occurrence, an aromatic or heteroaromatic ring system having 5 to 40 aromatic ring atoms, which may in each case be substituted by one or more radicals R 2 ; R 2 is selected on each occurrence, identically or differently, from the group consisting of H, D, an aliphatic hydrocarbon radical having 1 to 10 C atoms, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may be substituted by one or more alkyl groups having in each case 1 to 4 carbon atoms; <EOS>