A series of 2-(N-arylsulfonylindol-3-yl)-3-aryl-1,3-thiazinan-4-one derivatives were synthesized and evaluated in vitro against seven phytopathogenic fungi, namely Fusarium graminearum, Alternaria solani, Fusarium oxysporium f. sp. vasinfectum, Alternaria brassicae, Valsa mali, Alternaria alternata, and Pyricularia oryzae. Among all derivatives, especially compound 4j exhibited a potential antifungal activity against four phytopathogenic fungi.