Insoluble in water and ethanol, slightly soluble in acetone, chloroform, o-chlorophenol, pyridine, toluene, and soluble in tetrahydronaphthalene and xylene (a reddish-red Chemicalbook fluorescent solution). It is purple-black in concentrated sulfuric acid, and produces a purple-black precipitate after dilution. It is dark purple in alkaline solution of hydrosulfite and dark red in acidic solution.Mainly used for dyeing and printing of cotton fabrics