Dibenzo-7-phosphanorbornadiene-substituted diazene MesN 2 PA (1, where Mes = mesityl, A = anthracene, or C 14 H 10 ), a synthetic equivalent of mesitylphosphaazide (MesN 2 P) and anthracene, was synthesized by treatment of [Ph 3 BPA][Na(OEt 2 ) 2 ] with [MesN 2 ]OTf (OTf = CF 3 SO 3 − ) in thawing tetrahydrofuran (14% isolated yield). Treatment of 1 with unsaturated molecules cyclooctyne, [Na(dioxane) 2.5 ][OCP] (phosphaethynolate), and Ad−CP (Ad = adamantyl) results in the corresponding [3 + 2] phosphaazide-(phospha)alkyne cycloadducts, with concomitant loss of anthracene in 65%, 49%, and 38% isolated yield, respectively. Structural data for the phosphaethynolate cycloadduct ) 2 ]) were obtained in a single-crystal X-ray diffraction study. A diazatriphosphole was generated by combining 1 with P 2 A 2 , a thermally activated anthracenebased molecular precursor to diphosphorus (P 2 ). Thermolysis (33−65 °C) of 1 in benzene-d 6 leads to anthracene extrusion. This process has a unimolecular kinetic profile and proceeds with activation parameters of ΔH ⧧ = 21.6 ± 0.3 kcal/mol and ΔS ⧧ = −4.9 ± 0.8 cal/(mol K).