Metal carbene complexes comprising at least one imidazo-quinoxaline ligand, organic electronic devices, especially OLEDs (Organic Light-Emitting Diodes) which comprise such complexes, a light-emitting layer comprising at least one inventive metal carbene complex, an apparatus selected from the group consisting of illuminating elements, stationary visual display units and mobile visual display units comprising such an OLED, the use of such a metal carbene complex for electrophotographic photoreceptors, photoelectric converters, organic solar cells (organic photovoltaics), switching elements, organic light emitting field effect transistors (OLEFETs), image sensors, dye lasers and electroluminescent devices and a process for preparing such metal carbene complexes.