Synonyms: 2-Naphthalenecarboxamide,N,N'-(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis[4-[(2-chlorophenyl)azo]-3-hydroxy-(9CI); 4',4'''-Bi-2-naphthanilide,2',2'''-dichloro-4,4''-bis[(o-chlorophenyl)azo]-3,3''-dihydroxy- (6CI,8CI);C.I. 20050; C.I. Pigment Orange 31; Cromophtal Orange 4R; Pigment Orange 31