An electrochemical Study of several azo-azulene compounds (Az-N=N-Y, where Y = substituted phenyl, pyridine, thiazole) was performed with cyclic and differential Pulse voltammetry, as well as rotating-disk electrode methods. The objective of this work was to characterize their electrochemical properties and establish the influence of donor and acceptor substituents on azulene and azo group behaviour. Calculations were performed, using quantum mechanics-based methods, to correlate electrochemical reactivity with structure. Satisfactory correlations were found between experimental oxidation and reduction potentials as well as calculated ionization potentials and LUMOs. (C) 2008 Elsevier Ltd. All rights reserved.