A macrocyclic diimine crown ether, 2,3,11,12-dibenzo-5,9-diaza-4,9(10)-cis-diimino-1,13-dioxacyclopentadecane (O-en-N-tn), was synthesized and its electrochemical behavior reported. Reduction of -C=N- bonds was studied in an ethyl alcohol + water mixture (1:5 v/v) using sampled current polarographic, differential pulse polarographic, cyclic voltammetric, chronoamperometric and chronocoulometric techniques. A mechanism for the electrode reaction was proposed. The diffusion coefficient, heterogeneous rate constant and transfer coefficient of the electrode reaction were determined by choronoamperometric measurements. Adsorptional characteristics of the O-en-N-tn molecule on a mercury electrode were studied and the amount of molecules adsorbed was found to be of the order of 10(-12) mol cm(-2).