4,4'-Diaminobiphenyl-3-sulfonic acid

4,4'-diamino[1,1'-biphenyl]-3-sulphonic acid

4,4'-Diamino-(1,1'-biphenyl)-3-sulfonic acid

2-amino-5-(4-aminophenyl)benzenesulfonic acid

2-azanyl-5-(4-azanylphenyl)benzenesulfonic acid