The addition of acyclotriphosphine to abroad range of nitriles gives access to the first examples of free 1-aza-2,3,4triphospholenes in ar apid, ambient temperature,o ne-pot, high-yield protocol. The reaction produces electron-rich heterocycles (four lone pairs) and features homoatomic s-bond heterolysis,t herebyc ombining the key features of the 1,3dipolar cycloaddition chemistry of azides and cyclopropanes. Also reported is the first catalytic addition of PÀPbonds to the CNbond. The coordination chemistry of the new heterocycles is explored.