4-Di-phenyl-phosphanyl-8-methyl-1,5-naphthyridine.

In the title compound, C21H17N2P, the dihedral angles between the 1,5-naphthyridine ring system (r.m.s. deviation = 0.005 A) and the phenyl rings are 89.18 (8) and 77.39 (8)°. The phenyl rings are almost perpendicular, making a dihedral angle of 88.12 (8)°. The only possible inter­molecular inter­action is a very weak aromatic π–π stacking inter­action [centroid–centroid separation = 3.898 (2) A].