Abstract: | The preparation and X‐ray and spectroscopic studies of the title copper(II) complex, [Cu(C12H8N3O2)(CN)(H2O)], are reported. The CuII cation is five‐coordinated, forming a distorted square‐planar pyramid with an Addison τ parameter of 0.14. The UV–vis spectrum shows a d–d transition of the CuII centre at 638 nm, and the electron paramagnetic resonance (EPR) spectrum confirms that the CuII cation has an axial symmetry coordination and that the unpaired electrons occupy the dx2–y2 orbital. Cyclic voltammetric studies show two irreversible oxidation and reduction peaks. |