N, Ń-Bis [3-ethyl 2-azo (2-amino-8-hydroxy-nathalene-7-yl-6-sulphonic acid)- 4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylato-(N-4-chlorotriazino-6-yl)]-1, 4-phenylenediamine, Dye 2 : violet, m.p. >300°C, yield 80%, λmax(H2O) 561.8nm.

Figure 5: Structure of Dye 2.