Detailed insight into the electronic structure and bonding in heavy element chemistry remains poorly developed despite the critical role of actinide and lanthanide compounds in environmental, non-proliferation and energy issues. Furthermore, such insight into electronic structure in heavy element systems is critical in order to define the origins of their unique chemical properties as well as to broaden our understanding of fundamental quantum chemistry. Therefore, the Neidig group has been pursuing an exciting research direction focused on the development and applications of advanced inorganic spectroscopic methods to actinide chemistry as well as the synthetic and electronic structure studies of long-sought after uranium organometallic complexes in order to advance our understanding of electronic structure, bonding and reactivity in heavy element systems up to the level currently available for transition metals such as iron and palladium. . Representative contributions from our group in this area include (1) Synthesis and characterization of homoleptic uranium(IV)-aryl complexes, (2) Iinsight into the exceptional diversity of homoleptic uranium-methyl complexes, (3) Experimental and theoretical C-term MCD studies of the charge-transfer region UCl₆^- and (4) MCD studies to evaluate electronic structure in formal lanthanide(II) complexes. Additional work has been focused on the development of a ²³⁷Np Mössbauer capability and its application to understanding electronic structure and bonding in neptunium chemistry.