The need to develop energy sources that are clean and renewable is at the forefront of research. The demand for fossil fuels has led to a renewed focus to advance the study and efficiency of such energy processes. Of the many choices, one of the most promising emerging technologies is photovoltaic cells that can turn sunlight directly into energy or fuels. In order for these cells to replace former energy sources, it is necessary to increase the efficiency of them but at the same making sure that the costs associated with them remain low. The focus of this work will be on materials used as photon harvesters. These complexes absorb light and cause a charge transfer to occur. In order to increase the overall efficiency of photo-harvesting devices there are many different aspects that must be optimized. The maximum degree of the solar spectrum should be absorbed, in particular from 400 nm to 1200 nm. A material that has a broad, tunable absorption band is key to capturing as much of this light as possible. Also, the photo-harvester needs to have a high molar absorptivity in order to efficiently absorb these photons. Finally, it is vital that these materials possess long-lived charge separated excited state. With these long-lived states, charge transfer has ample time for injection into the acceptor upon visible light excitation, without charge recombination of the electron-hole pair. M2 quadruply bonded complexes, where M2 = Mo2, MoW or W2, have optical properties ideal for the aforementioned types of photon harvesters. Compounds of this type have a fully allowed metal-to-ligand charge transfer transition (MLCT) in the visible region that can be tuned to span the range of 400 nm to 1200 nm by careful tuning of the ligands and the metals in the paddlewheel structures. This absorption is quite intense with extinction coefficients that range from 20,000 to nearly 100,000 M-1cm-1. The MLCT is caused by the transfer of an electron from the M2d orbital to a ligand based p* orbital. The molecule exists in this singlet MLCT state for 3 – 30 ps before intersystem crossing to either a 3δδ* or 3MLCT state lasting from 2 ns upwards to ~75 µs. In depth study of the underlying electronic dynamics in these systems is needed first, with the focus being on how the charge is distributed in these systems upon visible light excitation, in addition to how long it resides there. These principles are necessary to design and produce more efficient devices that rely on charge injection. The Chisholm Lab has focused on these for some time, including the present. The complexes in this dissertation that have been synthesized and characterized are of the form trans-M2(TiPB)2L)2 where TiPB = 2,4,6-triisopropylbenzoate, L = extended-π conjugated carboxylates, and M = Mo or W. The electronic coupling in the mixed valent (MV) complexes of these photon harvesters is investigated with the introduction of extended π-ligands and how increased distance of the ligand has an effect on the coupling. Mixed valence systems follow one of two main motifs. The widely studied MV system [M-B-M]+ describes two metal redox centers connected by an organic bridge which facilitates electronic coupling to the redox centers, while studies of the [L-M-L]- system, corresponding to two organic ligand redox centers that are connected by a metal center, are more rare and understudied. In the initial chapter, chapter 3, the study of MV [L-M-L]- systems and the electronic coupling between extended ligands is investigated. UV-Vis-NIR spectroscopy and electrochemical measurements are vital in deducing the level of coupling between the two ligand redox centers mediated by the M2 core. In particular, the splitting in successive reduction events, ΔE, is a clear indication of the degree of ground state coupling in these [L-M-L]- systems. The appearance, shape, and energy of an intervalence-charge-transfer band in the NIR, from the chemically reduced anions, typically shows the Class and degree of the ground state electronic coupling. However, as in Chapter 3, this rule of thumb is not always reliable and the limits of its use as the ligands become longer is found. In chapter 4, the study of excited state coupling between the extended ligands in complexes similar to those of chapter 3 are studied. Substitution of the vinyl group for an ethynyl, isolated infra-red (IR) active group, is implemented and the excited state mixed valency investigated. Electronic structure calculations and time-resolved ultrafast spectroscopy aid in the investigation of determining the extent to which the two ligands share the electron in the excited state. The effect that adding boron to these extended p-complexes has on the excited state properties is also deduced. In chapter 5, by systematically increasing the distance of the ligand, the role that distance plays in the excited state electronic coupling between the ligands is investigated. Through the use of cross-coupled reactions on trans-terminal acetylene dimetallic synthons, the extended systems are effectively produced. By tracking of the charge in the ligand by multiple IR groups, installed at different distances in the ligand, the effect that distance partakes on the overall degree of delocalization is explored.