1-Phenyl-1H-naphtho-[1,2-e][1,3]oxazin-3(2H)-one

In the title compound, C(18)H(13)NO(2), the naphthalene (r.m.s. deviation = 0.025 Å) and benzaldehyde (r.m.s. deviation = 0.006 Å) groups are oriented at a dihedral angle of 89.48 (4)°. The oxazine group is oriented at dihedral angles of 13.36 (4) and 85.08 (5)°, respectively, with respect to the naphthalene and benzaldehyde fragments. In the crystal, inversion dimers linked by pairs of C-H⋯O hydrogen bonds generate R(2) (2)(8) loops. The dimers are linked into [010] chains via N-H⋯O hydrogen bonds. Weak C-H⋯π links and aromatic π-π stacking between the centroids of the naphthalene phenyl rings [centroid-centroid separation = 3.5977 (8) Å] help to consolidate the packing.