With the support of the Organic Dynamics Program and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate, Professor J. Devens Gust, Jr. and Professor Thomas A. Moore, of the Department of Chemistry and Biochemistry at Arizona State University, are carrying out photochemical studies of multicomponent molecular devices in solution and in organized assemblies. Natural photosynthetic reaction centers are photovoltaic devices of molecular dimensions, and the principles dictating the operation of reaction centers suggest design elements for synthetic optoelectronic switches. New types of pigments and electron donor and acceptor moieties, including functionalized buckminsterfullerenes, aromatic imides and amines, and porphyrin derivatives, are being used to construct molecular-scale photovoltaics, switches, and logic gates. Biomimetic antenna systems that gather light and transport excitation energy to these molecular photovoltaics and switches will also be studied. Incorporation of switches into larger-scale devices will be examined both by interfacing molecular species with microelectronic circuits and by incorporation of molecular photovoltaics into liposomes. Professor J. Devens Gust, Jr. and Professor Thomas A. Moore, of the Department of Chemistry and Biochemistry at Arizona State University, are supported by the Organic Dynamics Program and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate for their studies of molecules and molecular assemblies designed to harvest the energy of light. Modeling their studies after the structural motif designed by nature to carry out the process of photosynthesis, Professors Gust and Moore prepare and study molecules which absorb and use the energy of light. By appropriate design of molecular systems, these studies address the fundamental phenomena behind such interactions of molecules with light while paving the way for the preparation of molecular-scale electronic and computational devices which offer the possibility of optical processing and extraordinarily high density storage of information.