A compound of formula, Ir Formula wherein the ligand L has a structure of formula: wherein the ligand L coordinates to the iridium atom via the positions marked with * and wherein the hydrogen atoms not explicitly shown may also be partially or completely replaced by deuterium, and wherein the symbols and indices used apply: R at each occurrence is the same or different and is F or CN; Ar is a phenyl or biphenyl group which may be unsubstituted or substituted by one or more radicals, each of which are the same or different and are selected from the group consisting of F, CN, Si(CH 3) 3, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; in this case the phenyl or biphenyl group or the substituents on this phenyl or biphenyl group are optionally partially or completely deuterated; R 1 at each occurrence is the same or different and is F, CN, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms, a cyclic alkyl group having 4 to 8 C atoms, phenyl or biphenyl, wherein R 1 is optionally partially or completely deuterated; and wherein when two adjacent radicals R 1 represent a straight-chain, branched or cyclic alkyl group, the two radicals R 1 may form a ring system with one another; R 2, R 3 at each occurrence is the same or different and is F, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; wherein R 2 and R 3 are optionally partially or completely deuterated; and wherein two adjacent radicals R 2 or two adjacent radicals R 3 may form a ring system with one another; R 4 at each occurrence is the same or different and is a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms, a cyclic alkyl group having 4 to 8 C atoms, phenyl or biphenyl, wherein R 4 is optionally partially or completely deuterated; wherein when two adjacent radicals R 4 represent a straight-chain, branched or cyclic alkyl group, the two radicals R 4 may form a ring system with one another; R 5 at each occurrence is the same or different and is a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; wherein R 5 is optionally partially or fully deuterated; wherein two adjacent radicals R 5 may form a ring system with one another; R 6, R 7 at each occurrence is the same or different and is H, D, CH 3 or C 2 H 5, wherein the CH 3 group or the C 2 H 5 group is optionally partially or completely deuterated; r is 1 or 2; s is 0 or 1; m at each occurrence is the same or different and is 0, 1, 2, 3 or 4; n, o at each occurrence of is the same or different and is 0, 1, 2, or 3; p is 0, 1 or 2; q is 0, 1, 2, or 3; with the proviso that the sum of q + r + s ≤ 4. R at each occurrence is the same or different and is F or CN; Ar is a phenyl or biphenyl group which may be unsubstituted or substituted by one or more radicals, each of which are the same or different and are selected from the group consisting of F, CN, Si(CH 3) 3, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; in this case the phenyl or biphenyl group or the substituents on this phenyl or biphenyl group are optionally partially or completely deuterated; R 1 at each occurrence is the same or different and is F, CN, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms, a cyclic alkyl group having 4 to 8 C atoms, phenyl or biphenyl, wherein R 1 is optionally partially or completely deuterated; and wherein when two adjacent radicals R 1 represent a straight-chain, branched or cyclic alkyl group, the two radicals R 1 may form a ring system with one another; R 2, R 3 at each occurrence is the same or different and is F, a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; wherein R 2 and R 3 are optionally partially or completely deuterated; and wherein two adjacent radicals R 2 or two adjacent radicals R 3 may form a ring system with one another; R 4 at each occurrence is the same or different and is a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms, a cyclic alkyl group having 4 to 8 C atoms, phenyl or biphenyl, wherein R 4 is optionally partially or completely deuterated; wherein when two adjacent radicals R 4 represent a straight-chain, branched or cyclic alkyl group, the two radicals R 4 may form a ring system with one another; R 5 at each occurrence is the same or different and is a straight-chain alkyl group having 1 to 10 C atoms, a branched alkyl group having 3 to 10 C atoms or a cyclic alkyl group having 4 to 8 C atoms; wherein R 5 is optionally partially or fully deuterated; wherein two adjacent radicals R 5 may form a ring system with one another; R 6, R 7 at each occurrence is the same or different and is H, D, CH 3 or C 2 H 5, wherein the CH 3 group or the C 2 H 5 group is optionally partially or completely deuterated; r is 1 or 2; s is 0 or 1; m at each occurrence is the same or different and is 0, 1, 2, 3 or 4; n, o at each occurrence of is the same or different and is 0, 1, 2, or 3; p is 0, 1 or 2; q is 0, 1, 2, or 3; with the proviso that the sum of q + r + s ≤ 4.