Wiktionary
phthalonitrile
n. (context organic compound English) Any dinitrile derived from a phthalic acid
Wikipedia
Phthalonitrile
Phthalonitrile is an organic compound with the formula CH(CN), which is an off-white crystal solid at room temperature. It is a derivative of benzene, containing two adjacent nitrile groups. The compound has low solubility in water but is soluble in common organic solvents. The compound is used as a precursor to phthalocyanine and other pigments, fluorescent brighteners, and photographic sensitizers.