Three oxamido-bridged copper(II)-lanthanide(III) heterobinuclear complexes described by the overall formula Cu(oxen)Ln(phen)(2)(ClO4)(3) (oxen = N,N'-bis(2-aminoethyl)oxamide, Ln = Eu, Gd, and Er, phen = 1,10-phenanthroline), have been synthesized and characterized by the elemental analyses, IR spectroscopy, X-ray analysis and energy dispersive spectrometer (EDS) analysis. The thermal decomposition of the complexes was studied by TG, DTG, and DTA technique under dynamic nitrogen atmosphere. The decompositions of these complexes took place through four stages. The second and third stages were analyzed kinetically by means of the Achar method and the Coats-Redfern method. The activation energies, pre-exponential factors and the most probable kinetic model function were determined for these stages. (C) 2003 Elsevier B.V. All rights reserved.