Two new O, O′-dialkyl dithiophosphate-containing sulfido clusters, [WCu 3S 4(PPh 3) 3{S 2P(OCH 2Ph) 2}] 1 and [WAg 3OS 3(Ph 3P) 3{S 2P(OPr i) 2}] 2, were synthesized through reactions of [NH 4] 2[WS 4] with [CuS 2P(OCH 2Ph) 2] and [NH 4] 2[WOS 3] with [AgS 2P(OPr i) 2], respectively. Their crystal structures and nonlinear optical properties are reported. The X-ray crystallographic structure of 1 is an incomplete cubane-like structure, the dithiophosphate ligand adopts a triply bridging role, employing two sulfur atoms to coordinate to the three Cu atoms: one sulfur atom binds to one Cu atom, another sulfur atom to two other Cu atoms. The structure of 2 contains a half-open cubane-like cluster core, the dithiophosphate ligand acts as a bidentate ligand and the two S atoms of the di-isopropyl dithiophosphato ligand coordinate to two Ag atoms, respectively. Using a Z-scan technique with 532 nm laser radiation, both the real and imaginary parts of third-order nonlinear susceptibility of clusters 1 and 2 were determined.