Used as a dye in textile industries, particularly for dyeing cotton and other cellulosic fibers such as linen and viscose. It provides a bright blue color and is valued for its good solubility in water, making it suitable for dyeing processes that require uniform color distribution. Also applied in paper printing and sometimes in the formulation of inks. Due to its direct affinity to cellulose fibers, it is commonly used without mordants in dyeing operations. Limited use in biological staining applications for microscopy, though not common. Environmental concerns arise from its poor biodegradability, leading to wastewater treatment challenges in textile processing plants.