NOVELTY - Electronic device comprises an anode, a cathode and at least one metal compound (I) containing a metal-M co-ordinated to (hetero)aromatic ligands (II).    USE - (II) are useful in electronic devices, which are organic electroluminescent devices (organic or polymer light emitting diodes), 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 or organic laser diodes (all claimed).    ADVANTAGE - The electronic device exhibits improved durability, efficiency and operating voltage.    DETAILED DESCRIPTION - Electronic device comprises an anode, a cathode and at least one metal compound of formula (I) containing a metal-M co-ordinated to (hetero)aromatic ligands of formula (II).    M = Cu, Ag, Au, Zn, Sn, Pb, Ni, Pd or Pt;    V1 = B, BR-, CR, CO-, SiR, N, NR+, P, PR+, P(=O), As, AsR+, As(=O), Sb, SbR+, Sb(=O) or S+, or aliphatic or (hetero)aromatic cyclic groups with 3-6 ring atoms, where the part of the ligands L1-L3 are optionally covalently bonded together by Y1, and optionally substituted by one or more R;    Y1 = a bivalent group comprising CR2, BR, SiR2, NR, PR, P(=O)R, AsR, As(=O)R, SbR, Sb(=O)R, O, S, 1,2-vinylene or 1,2- or 1,3-phenylene, which are optionally substituted by one or more R;    a = 0 or 1;    b = 1-3, where b is 2 or 3 then a is 1;    L1 = 1-20C-heterocyclic containing at least one N (optionally substituted by one or more R, where the part of the heterocyclic group is bonded to M by a neutral or anionic nitrogen atom or by a neutral carbon atom) or 1-20C-(hetero)cyclic group, which is bonded to M by an exocyclic donor atom and optionally substituted by one or more R;    L2, L3 = a co-ordinating group, which is optionally substituted by one or more R, and is bonded to M by N, P, S or a neutral carbon atom, where L2 and/or L3 are same or different from L1;    L4 = any ligand, which is co-ordinated to M and is optionally substituted by one or more R, where L4 is optionally linked by a direct bond or by a bivalent group (Y1)n- with one or more of the part of the ligands L1-L3;    n = 0-3; either    R = linear 1-40C-alkyl or -(thio)alkoxy, branched or cyclic 3-40C-alkyl or -(thio)alkoxy, or 2-40C-alkenyl or -alkynyl (all optionally substituted by one or more R1, where one or more non-adjacent CH2-groups are optionally replaced by R1C=CR1, C?=C, Si(R1)2, Ge(R1)2, Sn(R1)2, C=O, C=S, C=Se, C=NR1, P(=O)(R1), SO, SO2, NR1, O, S or CONR1 and one or more H-atoms are optionally replaced by F, Cl, Br, I, CN or NO2), or 10-40 membered di(hetero)arylamino or arylheteroarylamino group, 5-60 membered-(hetero)aryloxy or (hetero)aralkyl, 5-60 membered (hetero)aromatic ring system (all optionally substituted by one or more R1), H, D, F, Cl, Br, I, N(R1)2, CN, NO2, OH, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1 or OSO2R1; or    two or more R together = mono- or polycyclic, aliphatic or (hetero)aromatic and/or benzo fused ring system; either    R1 = linear 1-40C-alkyl or -(thio)alkoxy, branched or cyclic 3-40C-alkyl or -(thio)alkoxy, or 2-40C-alkenyl or -alkynyl (all optionally substituted by one or more R2, where one or more non-adjacent CH2-groups are optionally replaced by R2C=CR2, C?=C, Si(R2)2, Ge(R2)2, Sn(R2)2, C=O, C=S, C=Se, C=NR2, P(=O)(R2), SO, SO2, NR2, O, S or CONR1 and one or more H-atoms are optionally replaced by F, Cl, Br, I, CN or NO2), or 10-40 membered di(hetero)arylamino or arylheteroarylamino group, 5-60 membered-(hetero)aryloxy or (hetero)aralkyl, 5-60 membered (hetero)aromatic ring system (all optionally substituted by one or more 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    two or more R1 together = mono- or polycyclic, aliphatic or (hetero)aromatic and/or benzo fused ring system; and either    R2 = 1-20C-aliphatic or (hetero)aromatic hydrocarbyl (optionally one or more H atoms are optionally replaced by F), H, D or F; or    two or more R2 together = mono- or polycyclic, aliphatic or (hetero)aromatic ring system.    INDEPENDENT CLAIMS are included for:    (1) (hetero)aromatic ligands of formula (IIa)-(IIe) (representative of (II)); and    (2) preparing (II), comprising reacting corresponding free ligands with metal salts or metal complexes of the corresponding metals.