The title mol­ecules were synthesized by alkyl­ation of 5-[(4-di­methyl­amino)­phen­yl]-1,3,4-oxa­diazole-2-thiol. In the crystals, C–H⋯π inter­actions are observed between neighboring mol­ecules. Hirshfeld surface analysis indicates that H⋯H and H⋯C/C⋯H inter­actions make the most important contributions to the crystal packing.