The reactions of jade-green Tp*(MoO)-O-IV(S2PR2) [Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate; R = Et, Pr-i, Ph] with propylene sulfide produce ochre-red Tp*(MoOS)-O-VI{SP(S)R-2}. The complexes have been characterized by microanalysis, mass spectrometry, cyclic voltammetry, spectroscopy (IR, NMR, UV-vis, and X-ray absorption), and X-ray crystallography. The distorted-octahedral isopropyl and phenyl derivatives feature a tridentate fac-Tp* ligand, a terminal oxo ligand, and a unique five-membered Mo(=S){SP(=S)R-2 ring moiety formed by a weak, intramolecular, bonding interaction between the MoS1 and (uncoordinated) S3P moieties. The MoS1 [2.227(2) angstrom (R = Pr-i) and 2.200(2) angstrom (R = Ph)] and S1 center dot center dot center dot S3 distances [2.396(3) angstrom (R = Pr-i) and 2.383(2) angstrom (R = Ph)] are indicative of a pi-bonded MoS1 unit and a weak (bond order ca. 1/3) S1 center dot center dot center dot S3 interaction; the solid-state structures are maintained in solution according to S K-edge X-ray absorption data. The complexes react with excess cyanide to form thiocyanate and Tp*MoO(S2PR2), under anaerobic conditions, or Tp*MoO2(S2PR2), under aerobic conditions; the latter models the production of thiocyanate and desulfo molybdenum hydroxylases upon cyanolysis of molybdenum hydroxylases. The complexes react with triphenylphosphine to give Tp*MoO(S2PR2) and SPPh3, with cobaltocene or hydrosulfide ion to produce [Tp*(MoOS)-O-V(S2PR2)](-), and with ferrocenium salts to yield [Tp*(MoO)-O-V(S3PR2)](+); in the last two reactions, Mo(V) is produced by direct or induced internal redox reactions, respectively. The presence of the Mo(O)S center dot center dot center dot S interaction does not radically lengthen the MoS bond in the complexes or preclude them from reactions typical of unperturbed oxosulfidomolybdenum(VI) complexes.