By means of liquid chromatography–mass spectrometry and other analytical methods, a variety of different samples of the phenazine dye Chrysaniline hosted in the Historical Dyestuff Collection of the Technical University Dresden and registered mostly under the trade name Phosphine have been analysed. It was found that all the dyes analysed are mixtures of compounds with different numbers of methyl groups at their phenazine core. They result, hence, from the oxidation of technical aniline that contained several amounts of isomeric toluidines and traces of dimethylanilines.