NOVELTY - Iridium complexes (I) are new.    USE - (I) are useful as emitting compound in an electronic device, photocatalyst or oxygen sensors, where the electronic device is organic electroluminescent devices (preferred), organic integrated circuit, organic field-effect transistors, organic thin-film transistors, organic light emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells or organic laser diodes; and for generating singlet oxygen (all claimed).    ADVANTAGE - (I) provide electroluminescent device with high service life, good thermal stability, high light-emitting efficiency and very low line voltage.    DETAILED DESCRIPTION - Iridium complexes of formula (Ir(L)n(L1a)m) (I) are new.    L = a substituted heteroaryl group of formula (II);    Z = CR or N, provided that if one of Z is N and then the other is CR;    Y1 = CR or N, provided that maximum Y1 is N, or two adjacent Y1 together forms a heteroaryl group of formula (III);    X = CR or N, provided that maximum two X per ligand are N;    R = linear 1-40C-alkyl, linear 1-40C-alkoxy, linear 1-40C-thioalkoxy, linear 2-40C-alkenyl, linear 2-40C-alkynyl, branched or cyclic 3-40C-alkyl, branched or cyclic 3-40C-alkenyl, branched or cyclic 3-40C-alkynyl, branched or cyclic 3-40C-alkoxy or branched or cyclic 3-40C-thioalkoxy (where nonadjacent CH2 groups are optionally replaced by R1C=CR1, Si(R1)2, C=O, NR1, O, S or CONR1 and one or more H-atoms are optionally replaced by D, CN, or F), 5-60 membered (hetero)aryl ring, 5-60 membered (hetero)aryloxy ring, 10-40 membered diarylamino, 10-40 membered diheteroarylamino, 10-40 membered arylheteroarylamino (all optionally substituted by R1), H, D, F, Cl, Br, I, N(R1)2, CN, Si(R1)3, B(OR1)2 or C(= O)R1, where two or more of R combined to form a mono- or polycyclic, aliphatic, aryl and/or benzo-fused ring system;    R1 = linear 1-40C-alkyl, linear 1-40C-alkoxy, linear 1-40C-thioalkoxy, linear 2-40C-alkenyl, linear 2-40C-alkynyl, branched or cyclic 3-40C-alkyl, branched or cyclic 3-40C-alkenyl, branched or cyclic 3-40C-alkynyl, branched or cyclic 3-40C-alkoxy, branched or cyclic 3-40C-thioalkoxy (where the non-adjacent CH2 groups are optionally replaced by R2C=CR2, Si(R2)2, C=O, NR2, O, S or CONR2 and H atoms are optionally replaced by D, F or CN), 5-60 membered (hetero)aryl ring system, 5-60 membered (hetero)aryloxy ring system, 10-40 membered di(hetero)arylamino, 10-40 membered arylheteroaryl amino (all optionally substituted by R2 ), H, D, F, N (R2)2, CN, Si(R2)3, B(OR2)2 or C(=O)R2, where two or more adjacent R1 together form a mono- or polycyclic, aliphatic ring system;    R2 = H, D, F or 1-20C-aliphatic or (hetero)aryl, preferably hydrocarbyl (in which at least one H atom is replaced by D or F), where two or more R2 together form a mono- or polycyclic, aliphatic or aryl ring system;    L1a = a mono- or bidentate ligand;    n = 1-3; and    m = 0-4.    INDEPENDENT CLAIMS are included for:    (1) the preparation of (I);    (2) a formulation comprising (I) and at least one further compound, preferably a solvent or its mixture; and    (3) an electronic device, preferably organic electroluminescent devices, organic integrated circuit, organic field-effect transistors, organic thin-film transistors, organic light emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells or organic laser diodes comprising (I).