C.I. 24410; C.I. Direct Blue 1; C.I. Direct Blue 1, tetrasodium salt; Direct Blue 1; chicago sky blue 6B (C.I. 24410); Pontamine Sky Blue 6BX; PontamineSkyBlueBX; Chicago Sky Blue?B; tetrasodium (6Z)-4-amino-6-({4'-[(2E)-2-(8-amino-1-oxo-5,7-disulfonatonaphthalen-2(1H)-ylidene)hydrazino]-3,3'-dimethoxybiphenyl-4-yl}hydrazono)-5-oxo-5,6-dihydronaphthalene-1,3-disulfonate; tetrasodium (6Z,6'Z)-6,6'-[(3,3'-dimethoxybiphenyl-4,4'-diyl)di(1Z)hydrazin-2-yl-1-ylidene]bis(4-amino-5-oxo-5,6-dihydronaphthalene-1,3-disulfonate)