Control experiments for varying amounts of BDP-TFP-COF (0-0.5 mg mL -1 ) showed negligible changes in absorbance in the absence of COF and increasing singlet oxygen generation at higher concentrations, thus evidencing that the presence of the COF is necessary for photosensitization (Figures ). Temporary irradiation by alternating light and dark cycles showed constant absorption in the dark, indicating that only light absorption by the COF triggers singlet oxygen generation (Figure ). Irradiation with different light sources Figures and) shows that the rate of singlet oxygen generation also depends on the irradiation wavelength. Under green LED light (~7 W, 528 nm) BDP-TFP-COF showed a better performance compared to amber (~7 W, 590 nm) or red (~7 W, 617 nm) LED lights. Since all three LED sources emit at wavelengths close to λmax(BDP-TFP-COF) = 575 nm (Figure ), this trend might be explained by the decreasing energy of photons at higher wavelengths.