Used in solid-phase synthesis of oligonucleotides for labeling DNA or RNA with a fluorescent dye. Enables real-time detection in sequencing, hybridization probes, and PCR assays. Commonly applied in molecular diagnostics, gene expression analysis, and fluorescence in situ hybridization (FISH). Provides high sensitivity due to strong fluorescence emission upon incorporation into nucleic acids. Ideal for automated synthesizers in research and clinical settings.