Novel bidentate Schiff base ligands, 2‐(2‐hydroxy‐5‐chloro/nitro)benzaldehyde‐[4‐(3‐methyl‐3‐mesitylcyclobutyl)‐1,3‐thiazol‐2‐yl]hydrazone, and their metal complexes have been prepared and characterized by elemental analyses, IR, 13C and 1H NMR spectra, and magnetic susceptibility measurements. All the complexes were found to be mononuclear. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:617–621, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10201