In this study, mixed ligand complexes derived from aceclofenac (Acecl) as primary ligand and 1,10-phenanthroline (Phen) as secondary ligand have been prepared and characterized by conventional techniques including elemental analyses, infrared, electronic spectra, 1H NMR and XRD. The infrared spectral data showed that the chelation behavior of the ligands towards Ni(II), Cu(II), Zn(II), Zr(IV) and La(III) transition metal ions is through oxygen of ketone, carboxylic group of aceclofenac and nitrogen atom of 1,10-phenanthroline. Thermal analyses showed that the chelates lose water molecules of hydration initially and subsequently expel anionic part and organic ligands in continuous steps leaving metal or metal oxide as a final product. XRD analysis of the compounds showed that, Acecl, Phen and their metal complexes display crystalline peaks.