NOVELTY - Metal complex compounds (I) are new.    USE - (I) are useful: in oligomer, dendrimer and polymer and formulation; as emitting compound in at least one emitting layer containing at least one matrix material, preferably ketones, phosphine oxides, sulfoxides, sulfones, triarylamines, carbazoles, indolocarbazoles, indenocarbazoles, azacarbazoles, bipolar matrix materials, silanes, azaboroles, boronic esters, di-azasiloles, diazaphospholes, triazines, zinc complexes, dibenzofurans and bridged carbazoles in an electronic device, preferably organic electroluminescent devices (preferred), organic integrated circuits, organic field effect transistor, 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 the generation of singlet oxygen; and in photocatalysis (all claimed).    ADVANTAGE - (I) provide emitter with improved efficiency, operating voltage, life time, color coordinates and color purity, and exhibit increased oxidation stability in solution.    DETAILED DESCRIPTION - Metal complex compounds of formula (M(L)n (L')m) (I) are new.    M (L)n=metal moiety of formula (II);    M=iridium or platinum;    D1=aryl or heteroaryl having 5-18C or fluoro (D1 is coordinated with carbon atom to M, optionally substituted with at least one R and is connected with D2 via a covalent bond);    X=CR or N;    W1=NR, O, S or CR2;    D2=5-18C heteroaryl (which is coordinated to M via a neutral N or carbene carbon atom optionally substituted with at least one R and is connected with D1 via a covalent bond), preferably N-containing heteocylic moieties;    R=straight chain alkyl, alkoxy or thioalkoxy having 1-20C, alkenyl or alkynyl having 2-20C, branched or cyclic alkyl, alkoxy or thioalkoxy having 3-20C (at least one non-adjacent CH2 is optionally replaced by R1C=CR1, C(C), Si(R1)2, C=O, NR1, O, S or CONR and at least one H is replaced by D, F, Cl, Br, I or CN), aryl or heteroaryl having 5-60C, aryloxy or heteroaryloxy having 5-40C, aralkyl or heteroaralkyl having 5-40C, diarylamino, di-heteroarylamino or arylheteroarylamino having 10-40C (all substituted by at least one R1, two adjacent R groups are fused together to form a mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring, in which out of two R groups, one is bonded to D2 and the other bonded to D1, or D1 and D2 contain two adjacent carbon atoms substituted by R are clamped on fused moiety of formula (III), preferably (hetero)aromatic moieties, 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;    R1=straight-chain alkyl, alkoxy or thioalkoxy having 1-20C, alkenyl or alkynyl having 2-20C, branched or cyclic alkyl, alkoxy or thioalkoxy having 3-20C (where at least one non-adjacent CH2 is replaced by R2C=CR2, C(C), Si(R2)2, C=O, NR2, O, S or CONR 2 and at least one H is replaced by D, F, Cl, Br, I, CN or NO2), aryl or heteroaryl having 5-60C, aryloxy or heteroaryloxy having 5-40C, aralkyl or heteroaralkyl having 5-40C, diarylamino, di-heteroarylamino or arylheteroarylamino having 10-40C (all optionally substituted by at least one 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, (where two adjacent R1 groups are fused together to form a mono- or polycyclic, aliphatic ring;    R2=H, D, F or aliphatic, aromatic and/or heteroaromatic hydrocarbyl having 1-20C (where at least one H is replaced by F and two R2 are fused together to form mono- or polycyclic, aliphatic ring;    L'=bidentate ligand which binds on M via a carbon atom and a nitrogen atom or two carbon atoms; either    n=1, 2 or 3;    M=iridium; or    n=1 or 2;    M=platinum; either    m=0, 1 or 2;    M=iridium; or    m=0 or 1;    M=platinum;    A=C(R1)2, O, S, NR3 or C (=O);    R3=straight chain alkyl or alkoxy having 1-20C, branched or cyclic alkyl or alkoxy having 3-20C (where at least one non-adjacent CH2 is replaced by R2C=CR2, C(C), Si(R2)2, C=O, NR2, O, S or CONR2 and at least one H is replaced by D or F), aromatic or heteroaromatic ring having 5-24C, aryloxy or heteroaryloxy having 5-24C, or aralkyl or heteroaralkyl having 5-24C (all optionally substituted by at least one R2), where two R3 are bonded to the same carbon atom are fused together to form aliphatic or aromatic ring, or spiro ring and R3 is connected with an adjacent R or R1 to form aliphatic ring; and    p=2 or 3.    Provided that: many ligands L or L is linked together with L' via a single bond or a bivalent or trivalent bridge and clamped as a tetradentates or hexadentates ligand system; two hetero atoms are not bonded directly in the group -(A)p; and L is either (II) or two groups (II) in which one is bonded to D1 and the other is bonded to D2. INDEPENDENT CLAIMS are also included for:    (1) preparation of (I);    (2) oligomer, dendrimer or polymer comprising (I), where at least one position of (I) is bonded to the polymer, oligomer or dendrimer; and    (3) formulation comprising (I) or the oligomer, polymer or dendrimer, and at least one further compound and/or a solvent.