Fourteen 2,3-cycloalkeno-chromones and -thiochromones (4H-benzo[b]thiapyrones) have been prepared by a new method in which enamines of cyclic ketones are condensed with the mixed anhydrides formed from ethylchloroformate and acetylsalicylic acids and their thio-analogues. An acyl migration occurs in the reactions of 2-pyrrolidinopropene to give 3-acyl-2-methylchromones.