In order to be able to continue using internal combustion engines in a sustainable manner, it must be ensured that these engines are operated exclusively with renewable, CO2-neutral fuels (e-fuels). An elegant way ito proof this is the use of a fluorescence sensor in the vehicle in combination with fuels that are labeled with a fluorescence marker. In this study we show that the benzophenonexazine compound Nile red proves to be a suitable fluorescence marker for fuel labeling, since the emission spectrum of fuels labeled with Nile red is in a suitable range of λem ∽ 600 nm - 700 nm for sensory detection. Moreover, the fluorescence spectrum of this fluorescence marker proves to be stable to thermo-oxidative aging over 192 h. Additionally, we discovered that, based on the exemplary aging of two monoalcohols, Nile red shows an antioxidant effect with respect to fuel aging of at least 33%.