A series of new thiazolidin-5-one disperse dyes was synthesized from the reactions of 2-substituted 3-phenylthiazolidinones with various aryldiazonium chlorides. The synthesized dyes were characterized by UV-visible absorption, IR, NMR and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth on polyester fibers. The dyed fabrics show moderate to good fastness to light and very good to excellent fastness to washing and perspiration. Also, the assessment of color coordinates was discussed.