The formal two-electron reduction of the cyclo-tri(phosphonio)methanide dication 1²⁺ results in a ring-opening reaction via C-P bond cleavage to yield the unique phosphanyl-functionalized carbodiphosphorane 2. In situ spectroelectrochemical investigations of the reduction of dication 1²⁺ and the oxidation of 2 give insights into the mechanism of this unusual and reversible bond cleavage reaction. Compound 2 features in total three lone pairs of electrons, facilitating the preparation of mono-, di-, and trigold complexes.