Widely used in microbiology as a chromogenic substrate for detecting β-glucosidase activity. When cleaved by the enzyme, it releases an insoluble blue-colored indigo dye, enabling easy visualization of enzyme-producing colonies on agar plates. Commonly applied in selective media for identifying specific bacterial strains, such as certain Enterococcus and Listeria species. Also used in molecular biology for screening recombinant clones in systems where β-glucosidase serves as a reporter enzyme. Its specificity and clear color development make it valuable in diagnostic and research settings.