To provide a dye which has a good hue, which can form an image showing a high fastness under various using conditions and environmental conditions, and which is particularly suited for an ink, the dye is represents by formula (1):wherein R.sub.1 and R.sub.2 each independently represents a monovalent group, Z represents a nitrogen atom or a carbon atom to which a hydrogen atom or a monovalent group is bonded, and M represents a hydrogen atom or a cation, provided that the dye has two azo groups. ##STR00001##