In the present study, a series of thiodihydropyrimidine derivatives were synthesized from different substituted aromatic aldehydes, ethyl acetoacetate, and urea/thiourea using a bimetallic TUD‐1 catalyst. The structures of all the synthesized compounds were characterized by melting point determination, thin layer chromatography (TLC), infrared (IR), 1HNMR, and 13C‐NMR values. All the synthesized compounds