Thermolysis of the substrates was then proven and monitored by UV-Vis and 1 H NMR spectroscopies for all compounds. However, while for PCPA-O2 and PFPA-O2 significant O2 release was achieved only at T > 45 °C, the best ORA candidate DIPA-O2 displayed a t1/2 ≈ 40 minutes already at 37.5 °C.