Abstract: The present invention relates to a novel blue dye compound represented by Formula (1) as shown below, which can be synthesized without a dianisidine compound used for a raw material and can dye a cellulosic high molecular material to provide the blue dyed product that has a high color value, a good build-up and various kinds of good fastness; a method for dyeing a cellulosic high molecular material by using the same; and a cellulosic high molecular material dyed with the same. A formazan compound represented by (In Formula (1), R1 is hydrogen, sulfo, hydroxy, chloro, methoxy, carboxyl or alkyl; either of R2 and R3 is hydrogen and the other is sulfo; X is morpholino, 2-hydroxyethylamino or bis(2-hydroxyethyl)amino; and Y is a phenylene diimino represented by Formula (2) as shown below (In Formula (2), R4 is sulfo or carboxyl)) or the salt thereof.

Abstract: An azo compound which in the free acid form is represented by the following formula: ##STR1## where R.sub.1 stands for methyl, ethyl, R.sub.2 stands for hydrogen, methyl, methoxy or ethoxy, R.sub.3 stands for hydrogen or methyl, and K stands for ##STR2## wherein the benzene nucleus A may be further substituted by methyl, amino, acetylamino or methoxy or: ##STR3## wherein these naphthalene neuclei may be further substituted by hydroxy, amino or acetylamino, also a process for preparing the azo compound and a dyeing method using said azo compound.