Xanthene (9H-xanthene, 10H-9-oxaanthracene) is a yellow organic heterocyclic compound. Its chemical formula is C13H10O. It is soluble in diethyl ether. Its melting point is 101-102 °C and its boiling point is 310-312 °C. Xanthene is used as a fungicide and it is also a useful intermediate in organic synthesis.
Derivatives of xanthene are commonly referred to collectively as xanthenes, and among other uses are the basis of a class of dyes which includes fluorescein, eosins, and rhodamines. Xanthene dyes tend to be fluorescent, yellow to pink to bluish red, brilliant dyes. Many xanthene dyes can be prepared by condensation of derivates of phthalic anhydride with derivates of resorcinol or 3-aminophenol.