Used extensively in molecular biology as a substrate for detecting β-galactosidase activity. When cleaved by the enzyme, it produces an insoluble blue product, making it valuable for visualizing gene expression in techniques like X-gal staining. Commonly employed in cloning experiments to identify recombinant bacteria containing plasmids with lacZ gene inserts. Also utilized in histochemistry and cell biology to study cellular localization and activity of β-galactosidase in tissues and cells. Its sensitivity and specificity make it a preferred choice in research involving reporter gene assays and genetic engineering.