Our research is devoted to electronic excitations and functional properties of molecular single crystals, doped organic thin films, as well as single molecules. Disclosing and understanding fundamental optoelectronic processes enables the utilization of these unique properties in innovative device concepts, e. g. Organic Light Emitting Diodes (OLEDs), Organic Light Emitting Antennas (OLEAs), Organic Field Effect Transistors (OFET), ultrafast photo-switches and single photon sources.