The complexes Tp*WO2X react with sulfiding agents such as B2S3 or P4S10 to give the oxothio- and bis(thio)tungsten(VI) complexes Tp*WOSX (X = Cl-) and Tp*WS2X [X = Cl, S2PPh2-; Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate]. The reaction of Tp*WS2Cl with (i) PPh3 in pyridine and (ii) dimethyl sulfoxide affords Tp*WOSCl in good overall yield. The chloro complexes undergo metathesis with alkali metal salts to yield species of the type Tp*WOSX and Tp*WS2X [X = OPh-, SPh-, SePh-, (-)-mentholate]. The diamagnetic complexes exhibit NMR spectra indicative of C-1 (Tp*WOSX) or C-s (Tp*WS2X) Symmetry and IR spectra consistent with terminal oxo and thio ligation (v(W=O), 940-925 cm(-1); v(W=S) or V(WS2), 495-475 cm(-1)). Crystals of (R,S)-Tp*WOS {(-)-mentholate} are monoclinic, space group P2(1), with a = 11.983(2) Angstrom, b = 18.100(3) Angstrom, c 13.859(3) Angstrom, beta = 91.60(2) degrees ,V = 3004.6(8) Angstrom (3), and Z = 4. Crystals of Tp*WS2(OPh)-CH2Cl2 are orthorhombic, space group Pbca, with a 16.961(4) Angstrom, b = 33.098(7) Angstrom, c = 9.555(2) Angstrom, V = 5364(2) Angstrom (3), and Z = 8. The mononuclear, distorted-octahedral tungsten centers are coordinated by a tridentate Tp* ligand, an alkoxy or aryloxy ligand, and two terminal chalcogenide ligands. The average W=O and W=S distances are 1.726(7) and 2.125(2) Angstrom, respectively, and the O=W=S and S=W=S angles 102.9(3) and 102.9(1)degrees, respectively. The tungsten and sulfur X-ray absorption spectra of Tp*WOSCl and Tp*WS2Cl are consistent with the presence of terminal pi -bonded thio ligands in both complexes. The thio complexes generally undergo a reversible one-electron reduction at potentials significantly more positive than their oxo analogues. The chemical, spectroscopic, and electrochemical properties of the complexes are heavily influenced by the presence of W=S pi* frontier orbitals.