1 : 4-Diamino-2-aryloxy-3-sulphoanthraquinones are prepared by heating 1 : 4-diamino-2 : 3-dichloranthraquinones under atmospheric pressure with a phenol and a sulphite of a strong, preferably inorganic, base in the presence of water. In examples 1 : 4-diamino-2 : 3-dichloranthraquinone is boiled with phenol and aqueous sodium sulphite to give 1 : 4-diamino-2-phenoxy-3-sulphoanthraquinone; this product is saponified to the corresponding 2-oxy derivative by warming with dilute soda and it dyes wool from a faintly acid bath in blue-violet shades. The sodium sulphite may be replaced by the methylamine salt of sulphurous acid, and homologues and substitution products of phenol may replace the latter; thus when m-cresol is used 1 : 4-diamino-2-cresoxy-3-sulphoanthraquinone which dyes wool violet-blue shades is obtained. The dyestuffs produced from halogenphenols also yield violet dyeings on wool.