The Nile Blue A, with the CAS registry number 3625-57-8 and EINECS registry number 222-832-5, has the systematic name of bis[9-(diethylamino)-5H-benzo[a]phenoxazin-5-iminium] sulfate. It is a kind of dark green to black powder which is irritant to people, so while dealing with this chemical, you should not breathe dust and then try to avoid contact with skin and eyes. And the molecular formula of the chemical is C₄₀H₄₀N₆O₆S.

The characteristics of Nile Blue A are as followings: (1)ACD/LogP: 3.20; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 3.16; (4)ACD/LogD (pH 7.4): 3.2; (5)ACD/BCF (pH 5.5): 146.21; (6)ACD/BCF (pH 7.4): 159.97; (7)ACD/KOC (pH 5.5): 1202.37; (8)ACD/KOC (pH 7.4): 1315.54; (9)#H bond acceptors: 4; (10)#H bond donors: 1; (11)#Freely Rotating Bonds: 3; (12)Polar Surface Area: 27.84 Å²; (13)Flash Point: 248.8 °C; (14)Enthalpy of Vaporization: 75.38 kJ/mol; (15)Boiling Point: 487.9 °C at 760 mmHg; (16)Vapour Pressure: 1.14E-09 mmHg at 25°C.

Addtionally, the following datas could be converted into the molecular structure:
(1)SMILES: [O-]S([O-])(=O)=O.N=1c4c(OC=3C=1c2ccccc2\C(=[NH2+])\C=3)cc(cc4)N(CC)CC.N=2c4ccc(N(CC)CC)cc4O\C\3=CC(=[NH2+])/c1ccccc1C=2/3
(2)InChI: InChI=1/2C20H19N3O.H2O4S/c2*1-3-23(4-2)13-9-10-17-18(11-13)24-19-12-16(21)14-7-5-6-8-15(14)20(19)22-17;1-5(2,3)4/h2*5-12,21H,3-4H2,1-2H3;(H2,1,2,3,4)
(3)InChIKey: QIRDPEPUXNCOLD-UHFFFAOYAD

The toxicity data is as follows: