The 4-(p-Nitrophenylazo)-1-naphthol is an organic compound with the formula C₁₆H₁₁N₃O₃. The IUPAC name of this chemical is 4-[(4-nitrophenyl)hydrazinylidene]naphthalen-1-one. With the CAS registry number 5290-62-0, it is also named as p-Nitrphenylazo-alpha-naphthol. It is orange to brown powder or crystals which is stable and incompatible with strong oxidizing agents, strong bases. In addition, 4-(p-Nitrophenylazo)-1-naphthol is used in the determination of magnesium.

The other characteristics of this product can be summarized as: (1)ACD/LogP: 4.66; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 5; (4)ACD/LogD (pH 7.4): 5; (5)#H bond acceptors: 6; (6)#H bond donors: 1; (7)#Freely Rotating Bonds: 4; (8)Index of Refraction: 1.673; (9)Molar Refractivity: 81.256 cm³; (10)Molar Volume: 216.706 cm³; (11)Polarizability: 32.213×10^-24 cm³; (12)Surface Tension: 58.13 dyne/cm; (13)Enthalpy of Vaporization: 86.648 kJ/mol; (14)Vapour Pressure: 0 mmHg at 25°C; (15)Rotatable Bond Count: 2; (16)Tautomer Count: 3; (17)Exact Mass: 293.080041; (18)MonoIsotopic Mass: 293.080041; (19)Topological Polar Surface Area: 87.3; (20)Heavy Atom Count: 22; (21)Complexity: 501.

When you are using this chemical, please be cautious about it as the following:
It is highly flammable, so it should be kept away from sources of ignition. And it is also irritating to eyes, respiratory system and skin, so people must not breathe dust and avoid contact with skin and eyes. In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. If you want to contact this product, you must wear suitable protective clothing, gloves and eye/face protection. In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.)

People can use the following data to convert to the molecule structure. 
1. SMILES: [O-][N+](=O)c1ccc(cc1)/N=N/c2ccc(O)c3ccccc23;
2. InChI: InChI=1/C16H11N3O3/c20-16-10-9-15(13-3-1-2-4-14(13)16)18-17-11-5-7-12(8-6-11)19(21)22/h1-10,20H/b18-17+.

The following are the toxicity data which has been tested.