(also resorcin, m-dihydroxybenzene), colorless crystals with a sweetish taste that are readily soluble in water, alcohol, and ether. Resorcinol has a melting point of 110.8°C and a boiling point of 280.8°C.

Resorcinol is one of the simplest diatomic phenols, comparable to hydroquinone and pyrocatechol. It is produced industrially usually by alkaline fusion of m-benzenedisulfonic acid. It is used in the manufacture of resorcinol-aldehyde resins and azo dyes—for example, resorcinol yellow is obtained by the interaction of resorcinol with diazotized sulfanilic acid. Fluorescein, stabilizers, and plastifiers of macromolecular compounds, as well as explosives and medicinal preparations such as 4-hexylresorcinol (an anthelmintic), are also manufactured from resorcinol.

In analytical chemistry resorcinol is used to make colorimet-ric determinations of furfural, lignin, sugars, and elements such as zinc and lead. In medicine it is used in unguents and solutions to treat skin diseases.