Synthesis and physico-chemical properties of 3-(4-bromobenzyl)-, 3-(4-chlorobenzyl)-5-arylidene-thiazolidine-2,4-diones and 3-(4-chlorobenzyl)-4-thioxo-5-arylidene-thiazolidin-2- ones are described. Twelve new products were synthesized by the aldolisation-crotonisation reaction from aromatic aldehydes and N-alkylated thiazolidinediones or thioxothiazolidinones. Seven compounds were preliminary tested for their bacteriostatic activity.