Widely used in molecular biology and microbiology as a chromogenic substrate for detecting α-L-fucosidase enzyme activity. When the enzyme cleaves the glycosidic bond, it releases an indoxyl derivative that oxidizes to form a blue or purple insoluble precipitate, enabling visual detection. This reaction is commonly employed in histochemistry, enzyme assays, and screening recombinant cells in cloning procedures. It is particularly useful in reporter gene systems where α-L-fucosidase serves as the marker enzyme. The compound allows for sensitive and specific detection in both agar plates and solution-based assays.