The enol form of naf­aza­trom

In the crystal structure of the title compound, 3-methyl-1-[2-(2-naphthyl­oxy)­ethyl]-1H-pyrazol-5-ol (naf­aza­trom, Bay g 6575), C16H16N2O2, the enol form is present rather than the keto form. The pyrazole and naphthalene ring systems are planar and the angle between them is 66.76 (12)°. A strong O—H⋯N hydrogen bond forces the mol­ecules to form ribbons running along the b axis. Partial stacking of the naphthalene rings accounts for distinct hydro­philic and hydro­phobic regions in the crystal structure.