Several 5-arylidene-4-thioxo-thiazolidine-2-ones (3a-n) were synthesized and evaluated as antimicrobial agents against representative strains, including multidrug-resistant strains of clinical isolates. Also, the antiproliferative activity was evaluated against two human carcinoma cell lines (NCI-H292 and HEp-2). The compounds containing the 5-arylidene subunit presented greater antimicrobial activities against Gram positive bacteria, including the multidrug-resistant clinical isolates, than the 4-thioxo-thiazolidine-2-one. Important SAR information was also gathered, such as the contribution of thiocarbonyl attached at 4-position on the thiazolidine heterocyclic for antimicrobial properties. None of the derivatives exhibited significant antiproliferative activity against the human carcinoma cell lines.