Aniline Yellow was the first azo dye.
The second azo dye was Bismarck Brown in 1863.
Aniline Yellow was commercialized in 1864 as the first commercial azo dye, a year after aniline black.
Aniline Yellow is used in microscopy for vital staining,[1] in pyrotechnics for yellow colored smokes, in yellow pigments and inks including inks for inkjet printers.
It is also used in insecticides, lacquers, varnishes, waxes, oil stains, and styrene resins.