We present here the study of a symmetrically substituted viologen derivative, 1,1＇-dioctadecyl 4,4＇-bipyridinium salt, at the air-water interface and arranged in Langmuir-Blodgett (LB) films which were characterized using W-vis spectroscopy. Detailed research of the electrochemical behavior of this molecule in LB films has been performed in terms of the nature of the counterion present in the water subphase, the number of layers, the transference pressure, and the nature of the electrolyte.