The chemoselective oxidation of sulfides to sulfoxides, catalysed by bridged, tetracyclic flavinium catalysts is presented. The flavinium catalysts are easily prepared via a telescoped three-step process. A range of sulfoxides is accessed in excellent yield and chemoselectivity.The chemoselective oxidation of sulfides to sulfoxides, catalysed by bridged, tetracyclic flavinium catalysts is presented. The flavinium catalysts are easily prepared via a telescoped three-step process. A range of sulfoxides is accessed in excellent yield and chemoselectivity.