The molecular structure of the selenides of [R2P(Se)]2Se type has been systematically studied on example of bis(dicyclohexylselenophosphinyl)selenide, [Cy2P(Se)]2Se. This selenide has been synthesized in 65% yield by oxidation of Cy2PH with elemental selenium in 1:2 M ratio. Its structure has been investigated by X-ray diffractometry (XRD), NMR, FT-IR and MALDI-TOF/MS techniques. In the solid, the Se1–P–Se2–P–Se3 chain of (Cy2P = Se)2Se molecule adopts a syn-anti conformation with the Se1–P–Se2–P and P–Se2–P–Se3 torsion angles of −179.64 (3)° and 4.69 (4)°. The vibrational band assignments, performing at B3LYP/6-311++G (d,p) theory level, are in a good agreement with the experimental FT-IR frequencies. The synthetic utility of the prepared selenide has been exemplified by its reaction with CuCl2 resulted in the formation of [Cu4(Se2PCy2)4] cluster in 53% yield. The structure of latter is formed by a Cu4 tetrahedron, wherein each triangular face is bridged by a [Se2PCy2] ligand in a trimetallic triconnective (μ2, μ1) pattern.