The first example of a stable phenylsulfaneselenolate species was synthesized in a one-step process and isolated as the tetraphenylphosphonium salt [PPh4][PhSSe] as indicated by X-ray crystal structure analysis. Electrospray ionization mass spectrometry and NMR studies in solution showed the compound to enter a complex system of equilibria when dissolved. Computations suggested a high barrier for rotation around the CS bond, indicating a pi-system conjugated over the whole molecule. In general, the compound is closely related to the recently isolated [PPh4][PhS2] perthiolate salt.