Redox stability of BIMEVOX.10 compounds (ME=Co, Cu) was studied using a technique involving electrochemical reduction followed by open-circuit (o.c.) relaxation. BICUVOX.10 and BICOVOX.10 were irreversibly reduced below -375 mV versus air and -530 mV versus air, respectively. Reaction paths were identified from thermodynamical considerations and Wavelength Dispersive Spectroscopy.