An improved experimental setup which allows the rigorous exclusion of oxygen and water from an electrochemical system has been successfully designed. The setup is based on degassing the solvent by sonication at reduced pressure, and then transferring it, on a vacuum line, to the electrochemical cell containing the dry compounds, through a previously activated alumina column. The capabilities of this setup for the study of oxygen- and water-sensitive electrochemical systems have been demonstrated in CH2Cl2 with anthracene, C-60, and Ru-3(CO)(12). Reversible cyclic voltammograms have been obtained for both the oxidation of anthracene to the radical cation and for its reduction to the radical anion. A reversible multielectronic oxidation process, as well as five reduction processes have been observed for C-60 in CH2Cl2 at room temperature, for the first time. On the other hand, reproducible cyclic voltammograms were obtained for 1 mM Ru-3(CO)(12) solutions, even when using the same solution and platinum electrode surface for a week.