Used primarily in biochemical research as a substrate for detecting β-galactosidase activity. This compound is particularly valuable in molecular biology for studying gene expression and regulation. When β-galactosidase acts on it, a colored or fluorescent product is released, making it useful in assays like X-gal staining. It helps in identifying and quantifying β-galactosidase in various biological samples, aiding in the analysis of cellular processes and genetic modifications.