NOVELTY - Substituted metal complexes (I) are new.    USE - (I) are useful: in electronic components including organic light-emitting devices/LEDs, organic integrated circuits, organic field effect transistors, organic thin film transistors, organic solar cells, organic light-emitting transistors, organic field quench devices, light-emitting electrochemical cells and organic laser diodes; as emitting material in an emitting layer of an organic electroluminescent device (all claimed).    ADVANTAGE - (I): have improved thermal stability so that the devices can be treated thermally without damage thus provides reproducible production of organic light-emitting devices/diodes, and low molecular weight of (I) provides vaporization in a high vacuum without decomposition; can be sublimed virtually without losses in the purification and production of devices; exhibit good solubility in organic solvents, which makes easy purification using recrystallization or chromatography, and improved oxidation stability, which has a positive effect on purification and handling; have improved operating lifetime; can be easily processed from solution using coating or printing techniques; and can be prepared reproducibly in high purity and display no batch-to-batch variation.    DETAILED DESCRIPTION - Substituted metal complexes of formula (M(L)n(L1)m(L2)o) (I) are new.    M = transition metal;    E = sp2-hybridized C or N;    Z = C(R)2 or NR;    M(L)n = substituted heterocycle moiety of formula (II);    either Cy1, Cy2 = optionally substituted heterocycle, which coordinates to M via the N atom and may have a bond to Z; and    R = 1-40C alkyl or alkoxy, 3-40C cycloalkyl or alkoxy, or 2-40C alkenyl or alkynyl (all optionally substituted by at least one non-adjacent CH2 optionally substituted by -R2C=CR2-, -CC-, Si(R2)2, Ge(R2)2, Sn(R2)2, -O-, -S-, -NR2-, -(C=O)-, -(C=NR2)-, -P=O(R2)-, SO, SO2 or -CONR2-), at least one H optionally substituted by F, (hetero)aromatic ring having 5-60 (hetero)aromatic ring atoms, (hetero)aryloxy having 5-60 aromatic ring atoms (optionally substituted by at least one nonaromatic R2), H, D, F or CN; or    RCy1Cy2 = aliphatic or (hetero)aromatic ring;    either R2 = 1-20C aliphatic hydrocarbon, (hetero)aromatic ring having 5-30 aromatic ring atoms (in which at least one H is optionally substituted by F, Cl, Br, I, CN, or NO2); or    at least two adjacent substituents R2 = form mono or polycyclic aliphatic, or (hetero)aromatic ring; and either    n = 1-3; and    m, o = 0-2; or    n+m+o = 2 or 3; and    L1, L2 = monodentate, bidentate or tridentate chelating ligands, which can also bind to L.    Provided that: n is 1 and L is tetradentate ligand, then (II) has no or one M-C bond, or tetradentate cyclic ligand; and (I) exclude from substituted metal-1,12-diaza-benzo(c)phenanthrene of formula (III).    M1 = transition metal;    Y1 = H, halo, carboxyl, carboxylate, optionally functionalized alkyl, OH or amino;    Y2 = H, halo, alkoxy, OH, nitro or amino; and    L3 = ligand.    INDEPENDENT CLAIMS are also included for:    (1) oligomer, polymer or dendrimer comprising (I); and    (2) an organic electroluminescent device comprising (I) that is used as emitting material in an emitting layer, preferably in combination with a matrix material comprising ketones, phosphine oxides, sulfoxides, sulfones, triarylamines, carbazole derivatives, indolocarbazole derivatives, azacarbazoles, bipolar matrix materials, silanes, azaboroles, boronic esters, triazine derivatives or zinc complexes, and/or is employed as matrix material for an emitting compound in an emitting layer and/or as hole-blocking material in a hole-blocking layer and/or as electron-transport material in an electron-transport layer and/or as hole-transport material in a hole-transport or a hole injection layer and/or as electron-blocking or exciton-blocking material in an exciton-blocking layer.