Ligation and mediated electro-oxidation of NO by the water soluble Ni(II) tetrasulfonated phthalocyanine (Ni(II)TSPc) at pH 7 to 9 is demonstrated using spectroscopic (ultraviolet-visible, Fourier transform infrared, and electron spin resonance) and electrochemical (cyclic voltammetry) techniques. The experimental results are in favor of the formation of a Ni(III)TSPc (NO-) complex in solution.