A new series of 3-(5-3-methyl-5-[(3-methyl-7-5-[2-(aryl)-4-oxo-1,3-thiazolan-3-yl]-1,3,4-thiadiazol-2-ylbenzo[b]furan-5-yl)methyl]benzo[b]furan-7-yl-1,3,4-thiadiazol-2-yl)-2-(aryl)-1,3-thiazolan-4-one 5a-j has been synthesized by the reaction of N2-[(E)-1-(4-methylphenyl)methylidene]-5-(3-methyl-5-[3-methyl-7-(5-[(E)-1-(4-methylphenyl)methylidene]amino-1,3,4-thiadiazol-2-yl)benzo[b]furan-5-yl]methylbenzo[b]furan-7-yl)-1,3,4-thiadiazol-2-amine 4a-j with thioglycolic acid. Chemical structures of all the new compounds were established by their IR, 1H-NMR, 13C-NMR, MS and elemental data. The 5a-j have been assayed for their nematicidal activity against Ditylenchus myceliophagus and Caenorhabditis elegans by aqueous in vitro screening technique. The screened data reveal that, the 5e is most effective against D. myceliophagus and C. elegans with 50% lethal dose (LD(50)) of 170 and 190 ppm, respectively and is almost equal to the activity of standard levamisole. The 5h and 5j are also most active against C. elegans with LD(50) of 200 ppm and D. myceliophagus with LD(50) of 190 ppm, respectively. Further, the 5a-j were screened for their antibacterial activity against three representative, Gram-positive bacteria viz. Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538p and Micrococcus luteus IFC 12708, and three Gram-negative bacteria viz. Proteus vulgaris ATCC 3851, Salmonella typhimurium ATCC 14028 and Escherichia coli ATCC 25922, and also screened for their antifungal activity against four fungal organisms viz. Candida albicans ATCC 10231, Aspergillus fumigatus HIC 6094, Trichophyton rubrum IFO 9185 and Trichophyton mentagrophytes IFO 40996. Most of these new compounds showed appreciable activity against the test bacteria and fungi, and emerged as potential molecules for further development.