Methyl violet 2B (Tetramethylparosanilinium chloride, 4,4'-[(4-Imino-2,5-cyclohexadien-1-yliden)methylen]bis(N,N-dimethylaniline)hydrochloride) is a violet triarylmethane dye from the group of cationic dyes and an essential component of C.I. Basic Violet 1 (trivial name methyl violet). Methyl violets are mixtures of tetramethyl (2B), pentamethyl (6B) and hexamethyl (10B) pararosanilins.[2]