The condensation of 4-amino-3-aryl-5-mercapto-1, 2, 4-tria-zoles (1a-f) with 6-/8-substituted 1,4-dihydro-4-oxo-quino-line-3-carboxylic acids (2a-d) in the presence of phosphorus oxychloride on refluxing or under microwave irradiation gave twenty four novel 3-aryl-6-(6-/8-substituted 4-chloroquinoline-3-yl)-s-triazolo[3,4-b]-1,3,4-thiadiazoles (4a-x), Consid-erable increase in the reaction rate has been observed with improved yields under microwave irradiation. The structures of the compounds synthesized were determined by elemental analyses, IR, 1H NMR and MS spectra. Their spectral properties and the reaction mechanism were also discussed. The preliminary biological test showed that some of compounds had moderate antibacterial activities.