Pyronin B is widely used as a biological stain in microscopy, particularly for nucleic acid detection. It binds selectively to RNA, allowing researchers to visualize and differentiate RNA within cells or tissues. This property makes it valuable in histology and cytology studies. Additionally, it is employed in fluorescence microscopy due to its ability to emit light when exposed to specific wavelengths, aiding in the study of cellular structures. Pyronin B is also utilized in flow cytometry for cell sorting and analysis, helping to identify and isolate specific cell populations based on RNA content. Its staining properties are further applied in electrophoresis techniques to detect RNA bands in gels.