In this study, we demonstrate an Ir(iii)-catalyzed thioether directed alkenylation of arene C–H bonds under mild reaction conditions.

The trifluoromethylthionyl group (−SCF3) is an efficient weak directing group for Ir­(III)-catalyzed aryl C–H olefination. Various trifluoromethylthioethers provide high levels of mono-olefination products in good to excellent yields under mild conditions with a 2,2′-bipyridine ligand or AgBF4 as an additive. Mechanistic studies indicate the C–H cleavage is the rate-determining step. The directing group ability of the −SCF3 group is benchmarked against several other weak directing groups by competition experiments under Ir­(III)-catalyzed conditions.