1,3-dihydro-2H-indol-2-ones derivatives are reported to exhibit a wide variety of biodynamic activities such as antituberculer, anti HIV, fungicidal, antibacterial, anticonvulsant. These valid observations led us to synthesize some new indole-2-one derivative. Thus, herein we report synthesis of various 5-substituted-3-[{5-(6-methyl-2-oxo/thioxo-4-phenyl-1,2,3,4 tetrahydro pyrimidin-5-yl)-1,3,4-thiadiazol-2-yl}imino]-1,3-dihydro-2H-indol-2-one derivatives 4a–l using one pot multicomponent–Biginelli reaction via CaCl₂ catalyst. Structures and purity of these compounds were confirmed by elemental, IR, (¹H & ¹³C) NMR and Mass spectral analysis. Newly synthesized compounds were also tested for their in vitro anti-tubercular activity against Mycobacterium tuberculosis H₃₇Rv, in vitro antibacterial activity against selected human pathogens viz. Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhi, Staphylococcus aureus, Staphylococcus pyogenus, Bacillus subtilis and antifungal activity against Candida albicans, Aspergillus niger, Aspergillus clavatus strains.