Syntheses of oxovanadium(V) thiolates such as O = V(SR) 3 (R = t C 4 H 9 , SiPh 3 ) and O=V(O t C 4 H 9 ) n (S t C 4 H 9 ) 3-n (n = 1, 2) are described. The thiovanadium(V) compounds S=V(O t C 4 H 9 ) 3 , S = V(S t C 4 H 9 )(O t C 4 H 9 ) 2 and S=V(SSiPh 3 ) 3 have been prepared by various methods :substition using Lawesson reagent, oxidation of V(O t C 4 H 9 ) 4 by sulfur, or disproportionation reaction of VCl 4 with LiSSiPh 3 ; O = V (OSiR 3 ) 3 (R = Me , Ph) undergoes a reaction with Lawesson reagent to yield dithiophosphonate complexes. All compounds obtained are characterized by 1 H and 51 V NMR spectroscopy; the stability of thiovanadium(V) compounds is discussed. V(S t C 4 H 9 ) 4 has been synthesized as a first example of vanadium(IV) thiolates