Efficient, green, and straightforward synthesis of 3,4-dihydropyrimidine-2(1H)-one/thione derivatives under favorable conditions has been achieved by reaction of urea/thiourea, aldehydes, and ethyl acetoacetate, using the synthetic potential of nanosilica-supported tin(II) chloride. It is noteworthy that the procedure has many advantages, for example excellent product yields, short reaction time, easy isolation of products, and reusability of catalyst. .