This dissertation investigates the chemistry of novel main group element-based dithiolene complexes. While the 1:2 reaction of chlorogermanium(IV) bis(dithiolene) complex (95) with N-heterocyclic carbene (NHC, 92) in the presence of H2O affords the first structurally characterized germanium(IV) tris(dithiolene) dianion (109) through carbene-mediated partial hydrolysis of the corresponding germanium(IV) bis(dithiolene) species, a series of low oxidation-state dithiolene-based germanium(II) complexes (110-113) has been synthesized. To study the cleavage of sulfur−sulfur bonds in an imidazole-based dithione dimer by a series of Lewis bases (i.e., carbenes, silylene, and phosphines), we synthesized the first carbene-stabilized dithiolene zwitterions (115 and 116), the spirocyclic silicon-dithiolene complex (117), the 1,2,5-trithiepin (118), the zwitterionic phosphine-dithiolene complex (120) and the thiophosphonate (121). The research project also investigated the reactivity of zwitterionic 115 with small molecules (i.e., NH3 and BH3·SMe2). The reaction of 115 with ammonia gives the dithiolene radical 123 and monothiolate 124 via single electron transfer (SET) and hydrogen atom transfer (HAT) processes. Zwitterionic 115 can also activate the B−H bonds in BH3·SMe2 to yield the dithiolene-based boranes (127 and 129) and doubly hydrogen-capped CAAC (128) through hydride-coupled reverse electron transfer (HCRET) processes. Remarkably, these are the first example of metal-free ammonia activation via HAT and the first observation of CAAC as a double-hydrogen-atom acceptor via HCRET. Additionally, the reactivity of dithiolene-based N-heterocyclic silane (117) with boron halides was explored. While 117 may serve as a double donor ligand to bind the stronger Lewis acids, BBr3 and BI3, at two nucleophilic sites—the terminal sulfur atom of the dithiolene unit and the backbone carbon of the N-heterocyclic silyl framework—yielding the zwitterionic Lewis adducts 138 and 143, respectively, the corresponding reaction of 117 with the weaker Lewis acid, BCl3, affords the dithiolene-substituted N-heterocyclic silane (145) through the cleavage of Si−S bond. This is a unique example of Lewis acid-induced charge separation of a five-membered N-heterocyclic silyl ring. The main group element-based dithiolene radical chemistry was also investigated with the synthesis of cationic magnesium(II) dithiolene monoradical (147) and aluminum(III) tris(dithiolene) triradical (148). Notably, 148 represents the first X-ray structurally characterized tris(dithiolene) triradical complex.