The anodic behavior of copper in a solution of dimethylamine and carbon dioxide in acetonitrile was studied using potentiodynamic and potentiostatic methods combined with microgravimetric methods utilizing an electrochemical quartz crystal microbalance (EQCM). The measurements are complemented by optical microscopy and scanning electron microscopy. Copper passivates anodically by forming a Cu2O layer at low overvoltage. Dissolution of the electrode as a soluble Cu(I)-product through the passive layer causes pitting. A kinetic model is suggested to reproduce the current transients at constant potentials in the Cu(I) region.