Described herein is the one-step synthesis of isothiazolone/1,2-selenazolone derivatives via [3+1+1] cycloaddition of cyclopropenone derivatives, anilines, and elemental chalcogens. The cascade reaction involves the C-S, C-N, and N-S bond formation along with the cleavage of C-C bond. Both anilines and cyclopropenones are tolerated and give the corresponding products in 28-73% yields.