Methyl Green is widely used as a biological stain in microscopy, particularly for identifying nucleic acids like DNA in cell nuclei. It binds selectively to DNA, allowing researchers to visualize and study cellular structures under a microscope. Additionally, it is employed in histology to differentiate tissues and in electrophoresis to track DNA fragments. In some cases, Methyl Green is also used as a pH indicator, changing color in response to acidity or alkalinity. Its staining properties make it a valuable tool in medical and biological research.