Sulfur K-edge X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculations have been used to determine the electronic structures of a series of Mo tris(dithiolene) complexes, [Mo(mdt)(3)](z) (where mdt = 1,2-dimethylethene-1,2-dithiolate(2-) and z = 2-, 1 -, 0), with near trigonal-prismatic geometries (D-3h symmetry). These results show that the formally Mo-IV, Mo-V, and Mo-VI complexes actually have a (dz(2))(2) configuration, that is, remain effectively Mo-IV despite oxidation, Comparisons with the XAS data of another set of Mo tris(dithiolene) complexes, [Mo(tbbdt)(3)](z) (where tbbdt = 3,5-ditert-butylbenzene-1,2-dithiolate(2-) and z = 1-, 0), show that both neutral complexes, [Mo(mdt)31 and [Mo(tbbdt)31, have similar electronic structures while the monoanions do not. Calculations reveal that the "Bailar twist" present in the crystal structure of [Mo(tbbdt)(3)](1-) (D-3 symmetry) but not [Mo(mdt)(3)](1-) (D-3h symmetry) is controlled by electronic factors which arise from bonding differences between the mdt and tbbdt ligands. In the former, configuration interaction between the Mo d(z)(2) and a deeper energy, occupied ligand orbital, which occurs in D-3 symmetry, destabilizes the Mo d(z)(2) to above another ligand orbital which is half-occupied in the D-3h [Mo(mdt)(3)](1-) complex. This leads to a metal d' configuration with no ligand holes (i.e., d(1)[L-3](0h)) for [Mo(tbbdt)(3)](1-) rather than the metal d(2) configuration with one ligand hole (i.e., d(2)[L-3](1h)) for [Mo(mdt)(3)](1-). Thus, the Bailar twist observed in some metal tris(dithiolene) complexes is the result of configuration interaction between metal and ligand orbitals and can be probed experimentally by S K-edge XAS.