The new tetradentate unsymmetrical N2O2 Schiff base ligands, Ni(II) and Cu(II) complexes were synthesised and chracterized by IR, UV–vis, 1H NMR and elemental analysis. The electrochemical properties of the Ni(II) complexes were investigated. The thermogravimetry of the Ni(II) and Cu(II) complexes were carried out in the range of 20–700 ◦C. Decomposition of synthesised complexes is related to the Schiff base characteristics.