Excitation energy migration followed by electron transfer forms the ma
in components of natural photosynthesis. An understanding of these asp
ects is essential to reenact the primary processes in laboratory under
conditions that are precisely repeatable. Here we describe the state
of understanding of the natural process and several model systems desi
gned to harvest solar energy and conversion to useful form of chemical
energy. The molecular assemblies constituting the model systems offer
a great advantage in terms of better comprehension of the mechanistic
aspects and yield valuable information on the design of molecular pho
tonic devices.