Abstract <p>This study aims to synthesize and perform a molecular docking study of some new heterocyclic compounds to evaluate their biological activity. The synthetic method includes several steps: formation of a new Schiff base via reaction of 5-amino-1,3,4-thiadiazole-2-thiol and 2-formylpyridine in an acidic medium and subsequent transformation to new heterocyclic compounds. The biological activity against two types of bacteria (<i>Escherichia coli</i> and <i>Staphylococcus</i> bacteria) was studied, the results showed good activity for some of these derivatives toward both targeted bacteria. The cytotoxicity of some of the synthesized derivatives was tested in vitro against esophageal cancer cell lines SK-GT-4, the results revealed that 8-hydroxy-3-(5-mercapto-1,3,4-thiadiazol-2-yl)-2-(pyridin-2-yl)-2<i>H</i>-benzo[<i>e</i>][1,3]thiazin-4(3<i>H</i>)-one and 5-[(1<i>H</i>-indol-3-yl)methyl]-3-(5-mercapto-1,3,4-thiadiazol-2-yl)-2-(pyridin-2-yl)imidazolidin-4-one exhibited inhibitory activity for SK-GT-4 with IC₅₀ values of 115.4 and 44.21μg/mL, respectively. A molecular docking study of these compounds confirmed the obtained results.</p>