NOVELTY - Metal complex compounds (I) are new.    USE - (I) or the oligomers, polymers or the dendrimers 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 (all claimed).    ADVANTAGE - The organic electroluminescent device exhibits good service life and excellent efficiency.    DETAILED DESCRIPTION - Metal complex compounds of formula (M(L)n(L1)m) (I) are new.    Either L = heterocyclyl moieties of formula (IIa)-(IIc); and    L1 = coligand; or    several L, L+L1 (bonded by single bond or by di- or trivalent bridge) = tridentate-, tetradentate-, pentadentate- or hexadentate ligand system;    M = transition metal;    Ar1 = heteroaryl having 5-18 aromatic ring atoms, which coordinates to M through N (optionally substituted by at least one group R);    A = C(R)2, C(=O), C(=NR) or Br; either    Z = CR or N; or    2 adjacent Z in (IIa) or (IIb) = heterocyclyl moieties of formula (IId);    Y1 = Z; either    R = 1-20C alkyl or 1-20C (thio)alkoxy (both linear) or 3-20C alkyl or 3-20C (thio)alkoxy (both branched or cyclic), 2-20C alkenyl or 2-20C alkynyl (in all groups at least one non-adjacent CH2 group is optionally replaced by R1C=CR1, CC, Si(R1)2, C=O, NR1, O, S or CONR1, and at least one H is optionally replaced by D, F, Cl, Br, I or CN), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-40 aromatic ring atoms, (hetero)aralkyl with 5-40 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, OH, COOH, C(=O)N(R1)2, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1 or OSO2R1, where one R may be additionally coordinated to the metal; and    R1 = 1-20C alkyl or 1-20C (thio)alkoxy (both linear) or 3-20C alkyl or 3-20C (thio)alkoxy (both branched or cyclic), 2-20C alkenyl or 2-20C alkynyl (in all groups at least one non-adjacent CH2 group is optionally replaced by R2C=CR2, CC, Si(R2)2, C=O, NR2, O, S or CONR2, and at least one H is optionally replaced by D, F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-40 aromatic ring atoms, (hetero)aralkyl with 5-40 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, Si(R2)3, B(OR2)2, C(=O)R2, P(=O)(R2)2, S(=O)R2, S(=O)2R2 or OSO2R2; or    at least 2 R = mono- or polycyclic and aliphatic or (hetero)aromatic ring; or    at least 2 adjacent R1 or R1+R = mono- or polycyclic and aliphatic or (hetero)aromatic 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 2 R2 = mono- or polycyclic and aliphatic ring;    n = 1-3; and    m = 0-4.    INDEPENDENT CLAIMS are also included for:    (1) preparing (I);    (2) an oligomer, polymer or dendrimer comprising (I) having at least one bond to the polymer, oligomer or the dendrimer; and    (3) an electronic device comprising (I) or the oligomer, polymer or dendrimer, preferably organic electroluminescent device, organic integrated circuit, organic field-effect transistor, organic thin-film transistor, organic light-emitting transistor, organic solar cell, organic optical detector, organic photoreceptor, organic field-quench device, light-emitting electrochemical cell and organic laser diode.