Janus Green B is widely used in biological and medical research as a vital stain for living cells. It is particularly valuable in histology and cytology for staining mitochondria, allowing researchers to observe and study mitochondrial activity and structure under a microscope. This dye is also employed in experiments involving cell viability and apoptosis, as it can differentiate between live and dead cells based on staining patterns. Additionally, Janus Green B is utilized in textile industries for dyeing silk and wool, providing vibrant and durable coloration. Its application extends to analytical chemistry, where it serves as an indicator in redox reactions due to its color-changing properties in response to oxidation states.