Compound of formula [Ir n (L') m] Formula where the compound of the general formula contains a substructure Ir n of the formula: where the symbols and indices used are as follows: Y is the same or different at each instance and is CR or N, with the proviso that not more than one symbol Y per cycle is N, or two adjacent symbols Y together are a group of the following formula: where the dotted bonds symbolize the linkage of this group in the ligand; X is the same or different at each instance and is CR or N, with the proviso that not more than two symbols X per ligand are N; R is the same or different at each instance and is H, D, Cl, Br, I, CN, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R 1 radicals; at the same time, two or more adjacent R radicals together may also form a mono- or polycyclic, aliphatic ring system; R 1 is the same or different at each instance and is H, a straight-chain alkyl group having 1 to 40 carbon atoms or a branched or cyclic alkyl group having 3 to 40 carbon atoms; L' is the same or different at each instance and is a mono- or bidentate ligand; n is 2 or 3; m is 0 or 1; characterized in that, in the substructure of the formula, two adjacent Y groups are CR and the respective R radicals together with the carbon atoms form a ring of the following formula or formula and/or in that two adjacent Y groups are a group of the formula and two adjacent X groups in this group of the formula are CR and the respective R radicals together with the carbon atoms form a ring of the following formula or formula: where R 1 and R 2 are as defined above, the dotted bonds signify the linkage of the two carbon atoms in the ligand and, in addition: A 1, A 3 is the same or different at each instance and is C(R 3) 2 or O; A 2 is C(R 1) 2; G is an alkylene group having 2 carbon atoms; R 3 is the same or different at each instance and is a straight-chain alkyl group having 1 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms, or an aromatic ring system having 5 to 24 aromatic ring atoms; at the same time, two R 3 radicals bonded to the same carbon atom together may form an aliphatic ring system and thus form a spiro system. Y is the same or different at each instance and is CR or N, with the proviso that not more than one symbol Y per cycle is N, or two adjacent symbols Y together are a group of the following formula: where the dotted bonds symbolize the linkage of this group in the ligand; X is the same or different at each instance and is CR or N, with the proviso that not more than two symbols X per ligand are N; R is the same or different at each instance and is H, D, Cl, Br, I, CN, a straight-chain alkyl or alkoxy group having 1 to 40 carbon atoms or a branched or cyclic alkyl or alkoxy group having 3 to 40 carbon atoms, or an aromatic or heteroaromatic ring system which has 5 to 60 aromatic ring atoms and may be substituted in each case by one or more R 1 radicals; at the same time, two or more adjacent R radicals together may also form a mono- or polycyclic, aliphatic ring system; R 1 is the same or different at each instance and is H, a straight-chain alkyl group having 1 to 40 carbon atoms or a branched or cyclic alkyl group having 3 to 40 carbon atoms; L' is the same or different at each instance and is a mono- or bidentate ligand; n is 2 or 3; m is 0 or 1; A 1, A 3 is the same or different at each instance and is C(R 3) 2 or O; A 2 is C(R 1) 2; G is an alkylene group having 2 carbon atoms; R 3 is the same or different at each instance and is a straight-chain alkyl group having 1 to 10 carbon atoms, a branched or cyclic alkyl group having 3 to 10 carbon atoms, or an aromatic ring system having 5 to 24 aromatic ring atoms; at the same time, two R 3 radicals bonded to the same carbon atom together may form an aliphatic ring system and thus form a spiro system.