NOVELTY - Metal complex compounds (I) are new.    USE - (I) are useful as emitting compounds in at least one emitting layer of electronic devices, preferably organic electroluminescent devices (preferred), organic integrated circuits, 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 and organic laser diodes; for producing singlet oxygen; and in photocatalysis or oxygen sensors (all claimed).    ADVANTAGE - (I) exhibit very good service life and very good efficiency, and requires very less operating voltage.    DETAILED DESCRIPTION - Metal complex compounds of formula (Ir(L)n(L1)m) (I) are new.    L = nitrogen-containing heterocyclyl moieties of formula (IIa);    X = CR or N, where not greater than 2 X per ligand = N; either    Y1 = CR or N, where not greater than 1 Y1 = N; or    Y1+Y1 = heterocyclyl moieties of formula (IIb); either    R = 1-40C alkyl or 1-40C (thio)alkoxy (both linear) or 2-40C alkenyl or 2-40C alkynyl (both branched) or 3-40C alkyl, 3-40C alkenyl, 3-40C alkynyl or 3-40C (thio)alkoxy (all branched or cyclic) (in all groups at least one non-adjacent CH2 group is optionally replaced by R1C=CR1, Si(R1)2, C=O, NR1, O, S or CONR1, and at least one H is optionally replaced by D, F or CN), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-60 aromatic ring atoms, diarylamino with 10-40 aromatic ring atoms, diheteroarylamino with 10-40 aromatic ring atoms or arylheteroarylamino with 10-40 aromatic ring atoms (all optionally substituted by at least one group R1), H, D, F, Cl, Br, I, N(R1)2, CN, Si(R1)3, B(OR1)2 or C(=O)R1; or    at least 2 adjacent R = mono- or polycyclic and aliphatic, aromatic and/or benzo-fused ring; either    R1 = 1-40C alkyl or 1-40C (thio)alkoxy (both linear) or 2-40C alkenyl or 2-40C alkynyl (both branched) or 3-40C alkyl, 3-40C alkenyl, 3-40C alkynyl or 3-40C (thio)alkoxy (all branched or cyclic) (in all groups at least one non-adjacent CH2 group is optionally replaced by R2C=CR2, Si(R2)2, C=O, NR2, O, S or CONR2, and at least one H is optionally replaced by D, F or CN), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-60 aromatic ring atoms, diarylamino with 10-40 aromatic ring atoms, diheteroarylamino with 10-40 aromatic ring atoms or arylheteroarylamino with 10-40 aromatic ring atoms (all optionally substituted by at least one group R2), H, D, F, N(R2)2, CN, Si(R2)3, B(OR2)2 or C(=O)R2; or    at least 2 adjacent R1 = mono- or polycyclic and aliphatic ring; either    R2 = aliphatic and/or (hetero)aromatic 1-20C organic group, preferably hydrocarbyl (in which at least one H is optionally replaced by D or F), H, D or F; or    at least 2 R2 = mono- or polycyclic and aliphatic or aromatic ring;    L1 = monoanionic bidentate ligand which is different from L, and containing coordinating atoms comprising C, N, O or S; and    n, m = 1 or 2.    INDEPENDENT CLAIMS are also included for:    (1) preparing (I); and    (2) a formulation comprising (I) and at least one further compound, preferably a solvent.