In the title compound, C(60)H(50)B(2)P(4)·1.5C(4)H(8)O, the diphospha-diborane mol-ecule lies on an inversion centre, whereas the disordered tetra-hydro-furan solvent mol-ecule is in a general position with a partial occupancy of 0.75. The diphosphadiborane mol-ecule consists of an ideal planar four-membered B(2)P(2) ring with an additional phenyl and a -PPh(2) group attached to each B atom.