A novel stable cyclic disilene, 1,2-diphenyl-3,3,6,6-tetrakis(trimethylsilyl)-1,2-disilacyclohexene (1), was synthesized via the reaction of the corresponding 1,4-dilithiobutane with phenylchlorosilane. This new strategy would be applicable to the synthesis of stable cyclic disilenes having rather small residual substituents on unsaturated silicon atoms. A stable tricoordinate Y-shaped disilene palladium complex, 2, that was synthesized by the reaction of 1 with bis(tricyclohexylphosphine)palladium was found to have the strongest pi-complex character among known disilene palladium complexes.