Oil Blue N is primarily used as a dye in various industries for staining and coloring purposes. It is commonly employed in the textile industry to dye synthetic fibers, providing a vibrant blue hue. In biological and histological studies, it serves as a staining agent to highlight specific structures or components under microscopic examination. Additionally, it is utilized in the petroleum industry to color oils and lubricants for identification and differentiation purposes. Its solubility in organic solvents makes it suitable for applications in non-aqueous systems, such as in the manufacturing of inks and coatings.