Thiazolobenzyne, which is a benzyne species fused with a thiazole ring, was efficiently generated via an iodine-magnesium exchange reaction of an ortho-iodoaryl triflate-type precursor using a trimethylsilylmethyl Grignard reagent as an activator. A wide range of arynophiles reacted efficiently with the thiazolobenzynes generated by this method to afford various multisubstituted benzothiazoles.