Photosensitizing properties were revealed by the generation of singlet oxygen in both H2O and organic solvents. Therefore, BDP-TFP-COF was used as an efficient and durable heterogeneous catalyst for the detoxification of a mustard gas simulant via selective photooxidation under visible light. The unique combination of chemical robustness, high adsorption capacity and photooxidation properties in the absence of heavy atoms renders BDP-TFP-COF as an intriguing candidate for unprecedented multifunctional applications.