Widely used in fluorescence labeling applications, this compound is ideal for conjugating to primary amines on proteins, peptides, and other biomolecules. Its bright red fluorescence makes it suitable for cellular imaging, including immunofluorescence, confocal microscopy, and flow cytometry. The dye is highly photostable and resistant to pH changes, providing consistent signal intensity in various biological environments. It is commonly used to label antibodies, streptavidin, and other detection reagents for multiplex assays where clear spectral separation is required. Due to its excellent brightness and specificity, it supports high-sensitivity detection in fixed and live-cell imaging studies.