In this paper, cubic nickel oxide nanoparticles were successfully prepared by solid-state thermal decomposition of nickel(II) macrocyclic Schiff-base complex at 450°C for 3 h without employing toxic solvent or surfactant and complicated equipment. nickel(II) macrocyclic Schiff-base complex was synthesized by the reaction of 1,2-bis(2-formyl-3-methoxyphenyl)propane, NiCl2•6H2O and 1,3-phenylenediamine in methanol at room temperature and characterized by elemental analyses and FT-IR spectroscopy. The as prepared NiO nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD pattern result shows that the synthesized NiO nanoparticles are pure and single phase. The SEM and TEM results show the morphology of the as prepared NiO nanoparticles is almost cubic shape with the average size between 20-150 nm. On the basis of the above results, other transition metal macrocyclic Schiff base complexes are therefore potentially capable of forming metal oxide nanoparticles. Manuscript profile