After studying the reaction scope, we focused to the reaction mechanism. EPR (Electron Paramagnetic Resonance) spectroscopy was used to identify the presence of key radical intermediates under the photochemical reaction conditions. We irradiated a solution of reagent I, NaBr and PC1 in the presence of radical trap 5,5-dimethyl-1-pyrrolineN-oxide (DMPO). Upon irradiating the mixture, the formation of an adduct was obtained supporting the formation of a trifluoromethylthio radical intermediate (g=2.006, aN=13.0G and aH=13.6G, a3F=1.9G 1.7G 1.9G) (Scheme 4, 1). 13 Scheme 3. Scope for the synthesis of vinyl-SCF3 Reactions were performed with 1 (0.2 mmol, 1 equiv.), reagent I (0.24 mmol, 1.2 equiv.), NaBr (0.2 mmol, 1 equiv.), PC1 (5 mol %) and MeCN (2 mL). The reaction mixture was stirred under blue LED irradiation for 16 hours unless otherwise noted. Isolated yields. Upon addition of styrene 1a to the previous reaction mixture, we detected the formation of two adducts reinforcing the formation of the trifluoromethylthio radical intermediate (g=2.006, aN=13.3G and aH=13.3G, a3F=1.9G, present in 81%) as well as a C-centred radical species that could potentially match with structure B (g=2.0056, aN=15.4G and aH=19.7G, present in 11%) (Scheme 4, 2).