NOVELTY - Metal complex compounds (I) are new.    USE - (I) are useful in at least one layer, preferably in an emitting layer as an emitter or a matrix, or in a hole blocking layer or an electron transport 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 high thermal stability, and can be readily synthesized. The electronic device exhibits high efficiency and long service life.    DETAILED DESCRIPTION - Metal complex compounds of formula (I) are new.    M = Cu, Ag, Au, Zn or Al;    A = N or P;    Y1 = divalent group, preferably CR2, O, S, 1,2-vinylene, 1,2-phenylene, 1,3-phenylene or ortho-linked heteroarylene with 5 or 6 aromatic ring atoms (all optionally substituted by at least one group R);    L1-L3 = heteroaryl with 5-25 aromatic ring atoms (optionally substituted by at least one group R, and containing N, S or O which coordinates with M) or (hetero)aryl with 5-18 aromatic ring atoms (optionally substituted by at least one group R, and containing exocyclic donor atom, preferably N, O, S or P which coordinates with M, and is optionally substituted by at least one group R), where partial ligands L1, L2 and L3 are bonded with each other through R which are bridged with one another; either    R = 1-40C alkyl or 1-40C (thio)alkoxy (both linear) or 3-40C alkyl or 3-40C (thio)alkoxy (both branched or cyclic) or 2-40C alkenyl or 2-40C alkynyl (in all groups at least one non-adjacent CH2 group is optionally replaced by R1C=CR1, CC, Si(R1)2, C=O, C=S, C=NR1, P(=O)(R1), SO, SO2, NR1, O, S or CONR1, and at least one H is optionally replaced by F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-60 aromatic ring atoms, (hetero)aralkyl 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, NO2, OR1, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1 or OSO2R1; or    at least two R = mono- or polycyclic- and aliphatic-, (hetero)aromatic- and/or benzo-fused ring; either    R1 = 1-40C alkyl or 1-40C (thio)alkoxy (both linear) or 3-40C alkyl or 3-40C (thio)alkoxy (both branched or cyclic) or 2-40C alkenyl or 2-40C alkynyl (in all groups at least one non-adjacent CH2 group is optionally replaced by R2C=CR2, CC, Si(R2)2, C=O, C=S, C=NR2, P(=O)(R2), SO, SO2, NR2, O, S or CONR2, and at least one H is optionally replaced by F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-60 aromatic ring atoms, (hetero)aralkyl 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, Cl, Br, I, N(R2)2, CN, NO2, OH, Si(R2)3, B(OR2)2, C(=O)R2, P(=O)(R2)2, S(=O)R2, S(=O)2R2 or OSO2R2; or    at least two R1 = mono- or polycyclic- and aliphatic-, (hetero)aromatic- and/or benzo-fused ring; either    R2 = aliphatic- and/or (hetero)aromatic 1-20C hydrocarbyl (in which at least one H is optionally replaced by F), H, D or F; or    at least two R2 = mono- or polycyclic- and aliphatic-, (hetero)aromatic- and/or benzo-fused ring; and    n = 0-5.    INDEPENDENT CLAIMS are also included for:    (1) preparing (I); and    (2) a formulation comprising (I) and at least one further compound, preferably a solvent.