TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The device further comprises a matrix material in at least one emitting layer, comprising a ketone, phosphine oxide, sulfoxide, sulfone, triarylamine, carbazole derivative, indolocarbazole derivative, indenocarbazole derivative, azacarbazole, bipolar matrix material, silane, azaborole, boronic ester, diazasilole derivative, diazaphosphole derivative, triazine derivative, zinc complex, dibenzofuran derivative, bridged carbazole derivative or a mixture of at least two of these materials.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): The preparation of (I), comprises reacting a free ligand with metal alkoxide compounds of formula (M(OR)n) (X), metal ketoketonate compounds of formula (XI), metal halide compounds of formula (M(Hal)n) (XII), dimeric metal complexes of formula (XIII) or metal complexes of formula ((((L1)m-M(L2)2)+)(Z)) (XIV).Hal = F, Cl, Br or I;L2 = alcohol or nitrile; andZ = non-coordinating anion.Preferred Method: The method also makes use of metal compounds which carry alkoxide-, halide-, hydroxy and ketoketonate groups. Preferred Components: (I) comprise heterocyclic complex compounds of formula (III)-(VIII).V1 = single bond, bridging unit comprising 1-80 atoms of third, fourth, fifth and/or sixth main group, or 3-6-membered homo- or heterocyclyl. Preferred Definitions:    M = Cr, Mo, W, Re, Ru, Os, Rh, Ir, Ni, Pd, Pt, Cu, Ag or Au, preferably Mo, W, Re, Ru, Os, Ir, Cu, Pt or Au;    G = ethylene (optionally substituted by at least one group R2);    R = CF3, OCF3, 1-10C alkyl, 1-10C alkoxy, (hetero)aromatic ring or (hetero)aralkyl (when at least one X = N and R is bonded adjacent to N) or (hetero)aryl, aryl cyanide, alkyl cyanide, aryl isocyanide, alkyl isocyanide, NH2, amide, alcohol, alkoxide, thioalcohol, thio-alcoholate, phosphine, phosphite, carbonyl, carboxylate, carbamide, aryl acetylidene or alkyl acetylidene (when R is bonded in ortho-position to metal coordination and is coordinated to M); and    L1 = CO, NO, alkyl cyanide, aryl cyanide, alkyl isocyanide, aryl isocyanide, NH2, phosphine, phosphite, arsine, stibine, nitrogen-containing heterocyclyl, carbene, hydride, deuteride, F-, Cl-, Br-, I-, alkyl acetylidene, aryl acetylidene, CN, cyanate, isocyanate, thiocyanate, isothiocyanate, aliphatic or aromatic alkoxide, aliphatic or aromatic thioalkoxide, amide, carboxylate, aryl, O2-, S2-, carbide (form (R-CM)), nitrene (form (R-N=M)), N3-, diamine, imine, diimine, heterocyclyl comprising 2 N, diphosphine, 1,3-diketonate derived from 1,3-diketone, 3-ketonate derived from 3-ketoester, carboxylate derived from amino-carboxylic acid, salicyliminate derived from salicylimine, dialkoxide, dithiolate, 3-(2-pyridyl)-diazole, 3-(2-pyridyl)-triazole, borate, nitrogen-containing heterocyclyl or bidentate monoanionic and neutral or dianionic ligand which with the metal form cyclometalated five- or six-membered ring having at least one metal-carbon bond.    SPECIFIC COMPOUNDS - Approximately 345 Compounds (I) are disclosed e.g. iridium complexes of formula (Ia)-(Ie).    EXAMPLE - Mixture of 10 mmol tris-acetylacetonato-iridium(III) and 60 mmol 8,8,10,10-tetramethyl-9,10-dihydro-8H-6a,12-diaza-benzo(a)cyclopenta(h)fluorene were heated at 260 degrees C for 100 hours, and the melted mixture was stirred. Then the mixture was cooled and the obtained sinter cake was washed with 100 g glass beads in 100 ml dichloromethane. Then the obtained fine suspension was decanted and the obtained solid was washed with 50 ml suspension medium, and then dried in vacuum. Then the obtained dry solid was treated with mesitylene. Then the obtained solution was worked up to obtain (Ia).