Used as a fluorescent probe in biological imaging due to its strong emission properties in the visible range. It readily enters cells and localizes in mitochondria, making it useful for tracking mitochondrial membrane potential in live-cell assays. Its sulfonate group enhances water solubility and reduces cellular toxicity, allowing for prolonged observation times. Also employed in photodynamic therapy research as a photosensitizer when paired with appropriate quenchers or energy acceptors. Additionally, serves as a building block in the synthesis of cyanine dyes for use in diagnostic labeling and biosensing applications.