TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The complex is used at a concentration of 1-30 wt.% together with at least one other material, particularly with at least one other matrix material. The complex (I) is applied onto a support or carrier. The application is performed by wet chemistry. The fraction of the complex in an emission layer is 100%. The fraction of the complex of the light emitter or the absorber is 0.1-99%. The concentration of the complex as a light emitter in optical light emitting elements, particularly in organic light-emitting diodes, is 1-20%.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): The complex (I) is formed by metal catalyzed coupling of precursor of formula (III) with charge transport group.C'1-C'4=reactive group (e.g. a halide, a boronic acid group, a boronic ester group, a vinyl group, an acetylenyl group, a trialkylstannane group) bound to a ligand (lig) consisting of aromatic groups Ar' (ar1 and ar2; ar3 and ar4);M1=metal ion (preferably a heavy metal, more preferably a d-block element, or a lanthanide);ar1-ar4=aromatic rings;ar1+ar2, ar3+ar4 (covalently-linked or fused) =five or six-membered aryl or heteroaryl or fused aryl or fused heteroaryl, where every ar1, ar2, ar3, and ar4 can comprise 2, 3, or 4 covalently linked or fused aromatic rings, and where the different ligands can also be linked by bridging groups, such as aryl and substituted aryl, amine, ether, oligo-ether, vinyl, alkene groups, aliphatic groups, spiro groups, silyl groups, borane groups, phosphane, arsane groups or silane groups;A1 and B1 and A' and B'=the coordination sites to the metal ion (preferably representing carbon or nitrogen);z1, z2, z3 and z4=1-4;n', m', o'=0-4;orn'+m'+o'=2-4.The sum of n', m', o' is 2 for a metal ion M1 with 4 coordination sites, 3 for a metal ion M1 with 6 coordination sites, 4 for a metal ion M1 with 8 coordination sites; and the ligands formed by ar1 and ar2 as well as ar3 and ar4 chelating to the metal ion M1 can be the same or different. Preferred Complex: The complex (I) is preferably compound of formula (I'). The complex comprises at least one ctg for transporting holes and at least one ctg for transporting electrons, thereby forming a bipolar complex capable of electron transport, hole transport, and light emission.ctg'1, ctg'2, ctg'3, and ctg'4=charge transporting groups and represent (preferably a conjugated hole or an electron transporting group comprising aryl or heteroaryl comprising nitrogen, oxygen, sulfur and/or a phosphorus atom being substituted covalently to ar1, ar2, ar3 and ar4, respectively). Preferred Definitions:    ctg=diarylamine, triarylamine, carbazole, thiophene, pyrrole, 3,4-ethylenedioxythiophene, fused thienothiophene, oligothiophene, tris(oligoarylenyl)amine, spiro compound or benzidine compound (all optionally substituted); oxadiazole, thiadiazole, triazole, benzimidazole, perylene and perylene derivatives, tris(phenylquinoxaline), silole compound, boron containing compound or pyridine (all substituted), fluoroaryl or fluoroheteroaryl;    lig=phenyl, biphenyl, phenol, pyridine, pyrimidine, pyrazine, triazine, pyrrole, pyrazole, imidiazole, triazole, thiophene, furan, thiazole, oxazole, oxadiazole, thiadiazole, naphalene, phenanthrene, fluorine, carbazole, benzothiophene, benzimidazole, benzothiazole or benzooxazole.    SPECIFIC COMPOUNDS - One compound is disclosed as (I) i.e. compound of formula (Ia).    EXAMPLE - mu -Dichlorotetrakis(2-(3-bromophenyl-3-bromopyridinato-kappa N,C)diiridium (97 mg) and diphenyl-(4-(4,4,5,5,-tetramethyl-(1,3,2)dioxaboralane-2-yl)amine (239 mg) and sodium carbonate (137 mg) were added distilled toluene (50 ml), absolute ethanol (20 ml) and distilled water (15 ml). The white suspension was degassed for half an hour before tetrakis(triphenylphosphine)palladium (30 mg) was added. The yellow biphasic mixture was heated to 80 degrees C and stirred under N2 overnight. After work up compound (Ia) (30 mg, 16.5%) was obtained as eluent.