Basic Brown 1, historically known as Bismarck Brown Y, is one of the earliest Disazo Dye. It produces a rich, yellowish-brown shade and is highly effective for staining anionic substrates. It is a versatile and highly economical colorant for a range of industrial applications. Its primary uses are in dyeing leather and paper, where it imparts a classic, durable brown colour. It is also a widely used biological stain in histology.