The isomer mixtures resulting from the diazotisation of 5,6-(6,7-)dichloro-2-aminobenzothiazole and coupling to N-substituted anilines were separable by column chromatography. Isomer characterisation was effected by unambiguous dye synthesis from the individual dichloro-2-aminobenzothiazoles, and by 1H NMR. The colour and dyeing parameters of isomers were found to be essentially equivalent, and similar to those of the corresponding isomer mixtures.