The reaction of various types of acetyl compounds with a ketene dithioacetal, methyl 2-cyano-3, 3-bis (methylthio) acrylate, in the presence of potassium hydroxide gave the corresponding 6-aryl-and 6-styryl-3-cyano-4-methylthio-2H-pyran-2-one derivatives. The methylthio group on the pyrone ring reacted readily with nucleophiles such as amines, active methylene compounds and methoxy anion to yield the corresponding displacement products in good yields.