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

In the title compound, C18H13NO2, the naphthalene (r.m.s. deviation = 0.025 angstrom) and benzaldehyde (r.m.s. deviation = 0.006 angstrom) groups are oriented at a dihedral angle of 89.48 (4)degrees. The oxazine group is oriented at dihedral angles of 13.36 (4) and 85.08 (5)degrees, respectively, with respect to the naphthalene and benzaldehyde fragments. In the crystal, inversion dimers linked by pairs of C-H center dot center dot center dot O hydrogen bonds generate R-2(2)(8) loops. The dimers are linked into [010] chains via N-H center dot center dot center dot O hydrogen bonds. Weak C-H center dot center dot center dot pi links and aromatic pi-pi stacking between the centroids of the naphthalene phenyl rings [centroid-centroid separation = 3.5977 (8) angstrom] help to consolidate the packing.