Since oxygen concentration is a critical parameter in various applications optical gas sensors are a field of intensive academic as well as industrial research. Nowadays indicator based optical oxygen sensors comprises in most cases a light source an immobilized transition metal complex for analyte determination and a detector system. In view of the fact that miniaturization of sensor elements is a key requirement, a novel electro-optical sensor device comprising the sensing as well as the light emitting functionality within one layer is demonstrated. This approach bridges the gap between organic light emitting devices (OLEDs), where transition metal complexes are used for device efficiency enhancement and classical optical oxygen probes. Based on a OLEDs comprising platinum-octaethylporphyrin immobilized in a poly(9-vinylcarbazole) we demonstrated the versatility of this new approach. Furthermore we were able to determine the indicator analyte interaction principle and showed the reversibility of this process.