The present invention relates to metal-carbene complexes of the general formula (I), where variable M is Ir or Pt and that are characterized by variable R being a group of formula (a). The complexes are used in organic electronic devices, especially OLEDs (Organic Light-Emitting Diodes), illuminating elements, stationary visual display units and in material layers as emitter, charge transport material and/or charge or exiton blocker.