The deposition of 4-nitroazobenzene (NAB) on carbon electrodes were achieved by the electrochemical reduction of 4-Nitro-4’-diazonium azobenzene tetrafluoroborate in anhydrous acetonitrile media using cyclic voltammetry technique at room temperature. The modified surfaces were examined as voltammetric electrodes for Fc/Fc⁺, Ru(NH₃)₆^3+/2+, IrCl₆^2-/3-, Fc(COOH)₂, Fe(phen)₃^3+/2+ and Ru(bpy)₃^3+/2+. The modified electrodes exhibited very slow electron transfer in compare to unmodified surfaces, by factors that varied with the redox systems. However, after scanning the modified electrode in 0.1M n-tetrabutylammonium tetrafluoroborate (TBABF₄) in acetonitrile from +0.4 to ∼ -0.9 V versus Ag/Ag⁺ for 25 cycles, the modified electrodes exhibited much faster electron transfer kinetics, for some redox systems approaching those observed on unmodified surfaces. The effect is attributed to an apparently irreversible structural change in the NAB monolayer, which increases the rate of electron tunnelling. The transition to the "ON" state is associated with electron injection into the monolayer. Once the monolayer is switched ON, it supports rapid electron exchange with redox systems, but not with dopamine, which requires adsorption to the electrode surfaces. A "switching" electrode may have the potential to impact the field of molecular electronics, which is one of the more popular areas of nanotechnology. [DOI: 10.1380/ejssnt.2006.419]