Simulation of photoelectric conversion in the photosynthetic reaction center by monomolecular layer assemblies of a folded or a linear type A-S-D triad carried out in this laboratory is reviewed. The oriented triad molecule acts as a charge separation unit and is named a molecular photodiode. The combined system with the linear triad and an antenna pigment is discussed next in terms of the charge separation and the light harvesting. Finally, electrocatalytic reduction of CO2 by alkyl Ni2+-cyclam derivatives studied is described. This monolayer can be used in artificial photosynthetic LB films as a catalytic layer which is deposited upon the electron-acceptor side of the charge separation layer in series.
