In search of novel antiviral and anticancer agents with promising pharmacotoxicological profile, a study was initiated to synthesize new 2-thioxo-4-thiazolidinones as well as 2-phenylimino-4-thiazolidinones substituted with benzimidazole ring system. The compounds were screened primarily for their antiviral as well as anticancer activities. The synthesis of some novel 5-substituted thiazolidinones was also described. None of the tested compounds showed inhibitory activity against Hepatitis C virus replication. Two 2-phenylimino-4-thiazolidinone derivatives (9a and 10) exhibited significant antiproliferative activity against human colon carcinoma cell line HCT 116 and human hepatocellular carcinoma HEPG2 cell line, respectively. Results also indicated that six thiazolidinone derivatives (5a, 5d, 5e, 5f, 5h, and 9d) showed moderate antiproliferative activity against human breast adenocarcinoma cell line MCF7 in comparison to the standard drug Doxorubicin. Moreover, a docked pose of the most potent three cytotoxic compounds 5a, 5h, and 9d against MCF7 was obtained bound to Human N-acetyl transferase1 NAT1 binding pocket by molecular operating environment module.