A facile synthesis of some novel 1,4-phenylene-bis(2-cyanomethyl-2-arylhydrazono-4-oxothiazolidin-5-ylidenes) 6a-f via reaction of 1,4-phenylene-bis(2-mercaptoacrylic acid) 4 with arylhydrazonomalononitriles 5a-f is discussed. Also, reaction of compound 4 with trichloroacetonitrile or other nitriles 10a-c gave 5,5‘-(1,4-phenylenebis(methan-1-yl-1-ylidene))-bis(thiazolidine-2,4-dione) 8. The prepared compounds are all reported for the first time and their structures are established by elemental and spectral data, and a plausible mechanism is postulated to account for their formation. All newly synthesized compounds show moderate to high antimicrobial activity.