Used in solid-phase oligonucleotide synthesis to introduce modified nucleobases into DNA strands. This modification enhances resistance to nuclease degradation and improves hybridization stability, making it valuable in antisense therapeutics, PCR primers, and probe design. Commonly applied in the development of diagnostic tools and gene-targeting drugs where increased binding specificity and biological stability are required. Also utilized in research settings to study nucleic acid interactions and enzyme mechanisms involving DNA polymerases and repair enzymes.