Benzimidazole-2-thiols and their transition metal complexes have been the focus of intense research due to their potential applications in bioinorganic and organometallic chemistry. Within this field of research, the synthesis and reactivity of benzimidazole thiones and selones bearing secondary alkyl substituents on both nitrogen atoms, iPr2bimE (E = S, Se), is described in this thesis. In order to investigate the significance of steric hindrance, the analogue of iPr2bimS bearing methyl substituents on the nitrogen atoms, Me2bimS, is also explored. In pursuance of establishing the coordination chemistry of these N-heterocyclic sulfur- and selenium- containing ligands, their reactivity towards closed-shell d10 metal ions such as copper(I), gold(I), and mercury(II) is examined. The structural differences and similarities among the iPr2bimE (E = S, Se) and Me2bimS complexes will be highlighted and the complete characterization of copper(I), gold(I), and mercury(II) complexes is discussed, including detailed structural information obtained using X-ray crystallography. Moreover, the enhanced selenophilicity of mercury, relative to its thiophilicity, is investigated using a combination of 1H NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS).