An asymmetric dioxazine compound of the following formula: ##STR1## wherein R is sulfo, halogeno, alkoxy, alkyl or carboxy; R.sub.1 and R.sub.2 are each hydrogen or alkyl; R.sub.3 is hydrogen, alkyl or acyl; X.sub.1 and X.sub.2 are each hydrogen, halogeno, alkyl, alkoxy or phenoxy; Y is aliphatic amino having a vinylsulfonyl or .beta.-substituted ethylsulfonyl fiber-reactive group; and Q is unsubstitued, substituted or cyclic amino; is useful for dyeing or printing fiber materials blue with excellence in build-up properties and various fastness properties.
