In this study, the electrochemical behavior of thianthrene (TH) and its application toward the electrocatalytic oxidation of guanosine (Gs) and DNA in a non-aqueous solution are investigated using different voltammetric techniques. Guanosine and DNA are adsorbed on the glassy carbon electrode (GCE) by applying a positive potential to the GCE. The rate constant of catalytic reaction between DNA and TH and also between Gs and TH were evaluated using chronoamperometry which gave rate constants of 2.41 x 10(6) cm(3) mol(-1) s(-1) and 2.68 (+/-0.19) x 10(6) cm(3) mol(-1) s(-1), respectively. Also the diffusion coefficient of TH was obtained using hydrodynamic voltammetry (3.17 x 10(-5) cm(2) s(-1)). Furthermore, using hydrodynamic voltammetry, a one-electron mechanism for oxidation of Gs is suggested. (C) 2010 Elsevier B.V. All rights reserved.