Nanostructures of two new copper(II) complexes, (CuL 1 ), 0.5EtOH. 1.5H 2 O (1), [H 2 L 1 =5-(4-Carboxy phenyl azo) anthranilic acid], (Cu(L 2 ) 2 ) (2), [HL 2 =1-(4-Carboxy phenyl azo) 2-naphtol] have been synthesized by the reaction of H 2 L 1 and HL 2 with Cu(OAc) 2 ·H 2 O through sonochemical process. Calcination of the nano-sized compounds 1–2 yield CuO nanoparticles at 550–450°C under air atmosphere. Metallic copper nanoparticles were prepared by direct calcination of compound 2 in surfactant at 180°C. These nanostructures were characterized by X-ray powder diffraction (XRD) and Scanning Electron Microscopy (SEM). Thermal stability of compounds 1–2 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).