To provide a new reactive azo dye having two azo groups and desirably used to dye or print hydroxy or amido substrates and a process for preparing the same.

This dye is represented by formula I (wherein D1 and D2 are each a benzene nucleus or a naphthalene nucleus; B1 and B2 are each a bridging group; X1 and X2 are each a fiber-reactive heterocyclic ring; Y is an aliphatic or aromatic bifunctional acyl; K1 and K2 are each a coupling component having at least two sulfo groups or a group of formula II; * is the position to which the azo group is bonded). An example is a good red dye represented by formula III (wherein the right and left parts of the benzene nucleus are symmetric) and is obtained by diazotizing aminodifluorochloriopyrimidinylaminobenzenesulfonic acid and reacting the product with terephthaloyl-H acid as a coupling component. It is generally obtained by e.g. diazotizing a diazo component represented by formula IV with and coupling the product with a coupling component represented by the formula: H-K1-Y-K2-H.