Naphthalenedisulfonic acid refers to organic compounds with the formula . They are derivatives of naphthalene. Twelve isomers are possible, but only a few have been examined in some depth, often as precursors to azo dyes or to various drugs. They are colorless solids with high solubility in water. Some derivatives are prepared by sulfonation of naphthalene or its monosulfonic acids. A few are produced by indirect routes.
In addition to these compounds, several naphthalenetrisulfonic acids are known as well as several hydroxy derivatives.