Used extensively in biochemical research for labeling proteins and peptides, enabling the study of protein interactions and dynamics. It is particularly valuable in fluorescence microscopy and flow cytometry, where its bright red fluorescence helps visualize and track cellular components. The maleimide group allows for specific conjugation to thiol groups in cysteine residues, making it a precise tool for site-specific labeling. Additionally, it is employed in FRET (Förster Resonance Energy Transfer) studies to investigate molecular distances and interactions. Its stability and high quantum yield make it a preferred choice for long-term imaging experiments.