A AgSCF₃-mediated tandem trifluoromethylthiolation and cyclization of N-aryl-3-butenamides was developed. It showed divergent reactivities and enabled the selective syntheses of CF₃S-substituted 3,4-dihydroquinolin-2-ones and azaspiro[4,5]dienones. The selectivity was achieved through different cyclization pathways of a CF₃S-substituted alkyl radical intermediate. It provides a useful tool for the synthesis of CF₃S-substituted N-heterocyclic compounds.