Used as a chromogenic substrate in enzymatic assays to detect and quantify β-L-fucosidase activity. Upon hydrolysis by the enzyme, it releases 4-nitrophenol, which produces a yellow color detectable at 400–410 nm, enabling real-time monitoring of enzyme kinetics. Commonly applied in biochemical research, diagnostic kits, and studies involving glycosidase enzymes in microbial, plant, and mammalian systems. Its colorimetric output allows for high-throughput screening and easy quantification in microplate assays.