1-Nitroso-2-naphthol is an organic compound with the formula . It is one of several possible nitrosonaphthols, and the most studied for applications as an indicator and a dye.
1-Nitroso-2-naphthol can be prepared by treatment of 2-naphthol with nitrous acid:
Its conjugate base forms deeply colored complexes with iron(II) and cobalt(II), complexes [M(C<sub>10</sub>H<sub>6</sub>(NO)O)<sub>3</sub>]<sup>2-</sup>. The deep colors of these complexes results from the delocalized bonding within each five-membered chelate ring. These species can be classified as nitroso complexes.