4-(4-Hydroxyphenylazo)-4'-(2-hydroxy-6,8-disulfo-1-naphtylazo)-1,1'-biphenyl

2-Hydroxy-1-[4'-(4-hydroxyphenylazo)-1,1'-biphenyl-4-ylazo]-6,8-naphthalenedisulfonic acid

7-Hydroxy-8-[[4'-[(4-hydroxyphenyl)azo]-1,1'-biphenyl-4-yl]azo]-1,3-naphthalenedisulfonic acid

7-Hydroxy-8-((4'-((4-hydroxyphenyl)azo)(1,1'-biphenyl)-4-yl)azo)naphthalene-1,3-disulfonic acid

7-hydroxy-8-[[4'-[(4-hydroxyphenyl)azo][1,1'-biphenyl]-4-yl]azo]naphthalene-1,3-disulphonic acid