In the present study a series of novel 2-(substituted phenyl)-3-(5-phenyl-1,3,4-thiadiazol-2-yl)-2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized by refluxing isatoic anhydride, 5-phenyl-1,3,4-thiadiazol-2-amine and aromatic aldehydes in the presence of p-TsOH as the catalyst and in H2O as the solvent and characterized by spectroscopic data and analytical methods. Antibacterial and antifungal activity of the title compounds were evaluated against two Gram positive and two Gram negative bacterial strains and strains of fungi and compared with standard drugs, using well diffusion method minimum bactericidal/fungicidal concentration were determined. The potential α-amylase and α-glucosidase inhibitory activity of compounds 4a-l were investigated in silico using molecular docking simulation method. Therefore, these 2,3-dihydroquinazolin-4(1H)-one derivatives may be considered as promising candidates for the development of new classes of antimicrobial and antidiabetic drugs.