Novel optical sensing films for oxygen based on highly luminescent iridium (III) and ruthenium (II) complexes have been developed. These demonstrate excellent long-term photostability (several months) when incorporated into polystyrene membranes. The influence of different plasticizers on the specific luminescence quantum yield, the Stern–Volmer constant, the reversibility and the response time were evaluated. Additionally the sensing films can be sterilized by chemical cleaning and gamma-ray irradiation.