To provide a water-soluble fiber-reactive dye which can be used at a low dyeing temperature, a method for producing the same and method for using the same.

A dye having at least one sulfo group and is represented by the formula (wherein F is a residue of a dye molecule; (n) is a number of 1 or 2; RA is hydrogen or a substituted or unsubstituted lower alkyl; RB is hydrogen, a substituted or unsubstituted lower alkyl or a substituted or unsubstituted phenyl; X is a halogen; R is hydrogen, a lower alkyl, a lower alkoxyl, a halogen or sulfo; and G together with the benzene ring forms a heterrocylic residue, provided that this may have at least one carbonylamino group the nitrogen atom of which may be substituted) is used to dye hydroxy and/or carboxyamide materials, especially fibrous materials such as fibrous cellulose materials, wool and synthetic polyamides.