Proton-monomeric ligand dissociation and metal-monomeric ligand stability constants of cinnamaldehyde anthranilic acid (CAA) with some transition metal ions were calculated potentiometrically in 0.1 M KCl and 50% (v/v) ethanol-water mixture. Also, in the presence of 2,2'-azobisisobutyronitrile as initiator the proton-polymeric ligand dissociation and metal-polymeric ligand stability constants were calculated. The effect of temperature on the dissociation of CAA and the stability of its formed complexes were studied in monomeric and polymeric forms. The corresponding thermodynamic functions were derived and discussed. The dissociation process is non-spontaneous, endothermic and entropically unfavourable. The formation of the metal complexes have been found to be spontaneous, endothermic and entropically favourable. (C) 2002 Elsevier Science B.V. All rights reserved.