Used in oligonucleotide synthesis as a protected intermediate, enabling selective modification and coupling reactions in the production of RNA-based therapeutics and research tools. The trityl group provides stability and prevents unwanted side reactions at the 5'-hydroxyl position during solid-phase synthesis. After chain assembly, the trityl group can be selectively removed under mild acidic conditions, allowing for further elongation or labeling. Commonly applied in the development of antisense oligonucleotides, siRNA, and diagnostic probes.