A series of new 2-(arylidene/5-arylfurfurylidene)-5-(4-methylthiophenyl)-6-carbethoxy-7-methyl-5H-thiazolo[2,3-b]pyrimidin-3(1H)-ones 2 and 3 have been synthesized by a three component (MCR) reaction involving 4-(4-methylthiophenyl)-5-carbethoxy-6-methyl-3,4-dihydropyrimidin-2(1H)-thione 1, monochloroacetic acid and arylaldehydes/arylfurfuraldehydes, respectively. The newly synthesized compounds were well characterized by elemental analysis, IR, (1)H NMR and mass spectral studies. The newly synthesized compounds were screened for their antibacterial and antifungal activities and have exhibited moderate to excellent growth inhibition of bacteria and fungi. The results of such studies have been discussed in this paper.