2-(4-Oxothiazolidin-2-ylidene) acetonitrile and ethyl -2-(4-oxothiazolidin-2-ylidene) acetate (1a, b), were condensed with anthralaldehyde (1:1 molar ratio) and gave 4, 5-dihydro-4-oxothiazole derivatives (2a, b). Refluxing of 2-(Antharacene-9-yl-methylene) malononitrile in acetic acid with thioglycollic acid gave (3). 4-Thiazolidinones containing bis aryl methylidine moieties (4a-c) and (5a, b) were produced via condensation of either (2a) or (3) with different aromatic aldehydes (1:1 molar ratio). Heating of (2a) with α-substituted cin- namonitriles gave the expected substituted thiazolo [3, 2-a] pyridines (6a-d), (8) and (10a-c). The synthesized compounds have been screened for their antimicrobial activities against some selected species of Gram-positive (G+). Gram-negative (G-) bacteria and 3 different types of fungi. They were found to be more active against Gram positive than Gram negative bacteria.