The primary focus of our research efforts is the elucidation of the structure and dynamics of photo-generated transient species. We have concentrated on two important photochemical systems: relaxation processes in organic electronic materials and energy and electron transfer in optical materials for solar energy conversion. A common thread that is emerging from our studies is the role of molecular conformation in determining both the chemical reaction pathways and the subsequent dynamics. Research in organic polymer materials for use in flexible Light Emitting Devices (LEDs) was initiated by the discovery of electroluminescence in poly(1,4-phenylenevinylene) (PPV). As a consequence of this discovery, increased attention to conducting polymers has produced many advances in the development of light emitting devices and polymer lasing media. In general, there is a strong correlation between electroluminescence and photoluminescence. Our research involves understanding the relationships among molecular structure, photoluminescence, and the photophysics of these materials in order to predict the luminescence behavior and to control the electroluminescence properties at the molecular level. Photosystem II (PS II) is a protein-pigment complex that catalyzes the light-dependent oxidation of water. Chlorophylls present in the PS II complex function in energy harvesting or as the primary electron donor during charge separation. Charge separation initiates electron transfer in the PSII reaction center resulting in the removal of electrons from water and release of molecular oxygen. The mechanism for energy and electron transfer in the PS II reaction center is not well understood and remains an active area of research. Site-directed mutagensis has proven to be a valuable tool in gaining further insight into the functionality of the PS II reaction center. We are using a variety of time-resolved spectroscopies to probe energy and electron transfer in wild type and mutant PS II reaction centers. We use pulsed lasers (10-13 to 10-9 seconds) to probe the initial photophysical processes in these systems. Transient absorption and time-resolved fluorescence are used to probe the electronic relaxation processes. We also use transient Raman spectroscopy and time-resolved infrared spectroscopy to probe the vibrational spectra of transient species. Vibrational spectroscopy gives direct structural information about conformational relaxation of intermediates and transient species.