The reactivity of electrochemically-active molecular architectures immobilized on electrode surfaces was investigated by electrochemical-TERS, at relatively high potential sweep rate and on broad potential ranges. A complex electrochemical mechanism, involving reaction intermediates and multiple reaction paths, could be resolved on electroactive architectures based on nitrobenzene derivatives. Further EC-TERS investigations on these derivatives assembled as mono- or multilayers on the electrode surface emphasized the influence of the structure of the molecular assemblies on their reactivity. Under specific conditions, azo bonds formation between nitrobenzene derivatives observed by TERS can result from the electrochemical polarization/reaction, and not from photochemical processes.