The title compound, C₁₆H₁₁N₂OF, is a member of the azo dye family. The dihedral angle subtended by the benzene ring and the naphthalene ring system measures 18.75 (7)°, indicating that the compound is not perfectly planar. An intramolecular N—H...O hydrogen bond occurs between the imino and carbonyl groups. In the crystal, the molecules are linked into inversion dimers by C—H...O interactions. Aromatic π–π stacking between the naphthalene ring systems lead to the formation of chains along [001]. A Hirshfeld surface analysis was undertaken to investigate and quantify the intermolecular interactions. In addition, energy frameworks were used to examine the cooperative effect of these intermolecular interactions across the crystal, showing dispersion energy to be the most influential factor in the crystal organization of the compound.

The title compound has been fully characterised by NMR for the first time. Fully assigned ¹H and ¹³C NMR spectra, and the X-ray structure of two different polymorphs are presented. The polymorphs show similar molecular geometries but exhibit significantly different patterns of intermolecular interactions.