Orange II sodium salt is widely used as a dye in various industries. It is commonly applied in the textile industry for dyeing fabrics, particularly wool, silk, and nylon, due to its vibrant orange color and good affinity for these materials. In biological research, it is used as a staining agent to visualize proteins and other biomolecules in gel electrophoresis. Additionally, it finds application in the paper industry for coloring paper products. Its water-soluble nature makes it suitable for use in inks and coatings. In some cases, it is also employed as an indicator in chemical reactions due to its color-changing properties under different pH conditions.