Synonyms: disodium 3-[[2,4-bis(2-methylphenoxy)phenyl]azo]-4-hydroxy-5-[[(p-tolyl)sulphonyl]amino]naphthalene-2,7-disulphonate;2,7-Naphthalenedisulfonic acid, 3-2,4-bis(2-methylphenoxy)phenylazo-4-hydroxy-5-(4-methylphenyl)sulfonylamino-, disodium salt;3-[2,4-Bis(2-methylphenoxy)phenylazo]-4-hydroxy-5-(4-methylphenylsulfonylamino)-2,7-naphthalenedisulfonic acid disodium salt