Synthetic routes leading to the formation of the first Pv-Pv compound, bis(cyclenphosphorane) (C8H16N4P)2 (3), are described. The coupling reaction between the lithiated derivative of cyclenphosphorane (1) and cyclenfluorophosphorane (2) yields 3. Bis(cyclenphosphorane) has also been detected as one of the products formed in the reaction of 1 and benzyl bromide. Single-crystal X-ray diffraction analysis shows that the macrocyclic nitrogen-containing ligands, N4(CH2)8, are arranged around the phosphorus atoms, giving a pentacoordinate geometry displaced 33% from the idealized trigonal bipyramid toward the square pyramid. 3 crystallizes in the orthorhombic space group Ccca, with a = 14.777 (6) Å, b - 14.549 (6) Å, c = 8.664 (3) Å, and Z = 4. Data were collected with an automated Enraf-Nonius CAD 4 diffractometer, out to a maximum 2θMoKα of 55°. Full-matrix least-squares refinement techniques led to the final agreement factors of R = 0.038 and Rw = 0.055 based on the 850 reflections having I ≥ 2σ1. A P-P bond length of 2.264 (2) Å was obtained, indicating normal stability of the Pv-Pv bond. The two symmetry related halves of the molecule are rotated 70° relative to each other, presumably to minimize steric interactions. The P-P midpoint is on a crystallographic 222 site.