Used extensively in fluorescence labeling and imaging applications, particularly in biological research. It serves as a reactive dye for conjugating with proteins, peptides, and antibodies, enabling visualization and tracking in cellular and molecular studies. Its high photostability and bright fluorescence make it ideal for confocal microscopy, flow cytometry, and super-resolution imaging. Commonly employed in live-cell imaging to study dynamic processes due to its cell-permeability and compatibility with various labeling protocols. Also utilized in fluorescence in situ hybridization (FISH) for detecting specific DNA or RNA sequences. Its succinimidyl ester group ensures efficient covalent bonding with primary amines, facilitating stable and specific labeling.