The reactions of [PPh4][(Et-S)WS3] in THF with N-methyliminodiacetic acid produced a new trinuclear cluster [PPh4]2[(S)2W(μ-S)2(O)W(THF)(μ-S)2W(S)2] 1 and its crystal structure was characterized by single-crystal X-ray analysis. 1 (C52H48O2P2S8W3) crystallizes in the monoclinic space group Cc with a = 19.661(3), b = 11.059(7), c = 25.545(2) , β= 107.493(8)°, V = 5297.4(9) 3, Z = 4, Mr = 1574.93, Dc = 1.975 g/cm3, F(000) = 3024, (MoK) = 69.22 cm-1 and T = 193 K. With the use of 8713 observed reflections (I > 3.0(I)), the structure was refined to R = 0.045 and Rw = 0.049. In the structure of the [(S)2W(μ-S)2(O)W(THF)(μ-S)2W(S)2]2- dianion, the central W(Ⅳ) atom is coordinated by two [WS4]2- ligands, one terminal O and one weakly bound THF molecule. The array of the three W atoms is bent (W(2)-W(1)-W(3) 156.63(3)°). The mean W-W bond distance is 2.998(6) A; and the mean lengths of the W-S bonds (those around the central W(1) atom, those bridging W(2) or W(3) atom, and the terminal ones) are 2.434(4), 2.263(4) and 2.150(4) A, respectively.