In this study, a novel Schiff-base of cysteine and saccharin [(2R)-2-(1, 1-dioxo-1, 2-dihydro-1 lambda 6-benzo[d]isothiazol-3-ylideneamino)-3-mercapto-propionic acid] was synthesized and characterized by UV-Vis, FT-IR, (1)H NMR and elemental analysis. The voltammetric behaviour of Schiff-base was investigated on the static mercury drop electrode (SMDE) by using Square-Wave voltammetry (SWV) and Cyclic voltammetry (CV). The voltammograms of the Schiff-base gave three reduction waves in Britton-Robinson buffer (pH 5.0-9.0) for the potential range from 0.0 to 1.4 V. The first reversible cathodic peak is due to reduction of the mercury thiolate, produced by the thiol group of Schiff-base which adsorbs at Hg electrode surface, to metallic mercury and free thiol. The second reduction peak may be assigned to the reduction of azomethine center (> C=N-) in the Schiff-base and the last peak may be related to the catalytic hydrogen reduction. (C) 2008 Elsevier B.V. All rights reserved.