Used as a fluorescent probe in biological imaging due to its ability to emit strong red fluorescence in cellular environments. It readily crosses cell membranes and accumulates in mitochondria, making it valuable for tracking mitochondrial activity and membrane potential in live cells. Also employed in photodynamic therapy research for its light-induced reactive oxygen species generation. Its ionic structure enhances solubility in aqueous media, supporting use in physiological studies. Additionally, serves as a building block in synthesizing quinolinium-based dyes and optoelectronic materials.