Synonyms: C.I. Direct Blue 53 (Tetrasodium salt);1,3-Naphthalenedisulfonic acid, 6,6'-((3,3'-dimethyl(1,1'-biphenyl)-4,4'-diyl)bis(azo))bis(4-amino-5-hydroxy-;6,6'-[(3,3'-dimethylbiphenyl-4,4'-diyl)dihydrazin-2-yl-1-ylidene]bis(4-amino-5-oxo-5,6-dihydronaphthalene-1,3-disulfonic acid);(6E,6'E)-6,6'-[(3,3'-dimethylbiphenyl-4,4'-diyl)di(1E)hydrazin-2-yl-1-ylidene]bis(4-amino-5-oxo-5,6-dihydronaphthalene-1,3-disulfonic acid)