Used in peptide synthesis as a protected cysteine derivative, enabling selective disulfide bond formation. The trityl group protects the thiol functionality, while the benzyloxycarbonyl (Cbz) group protects the amine. This selective protection allows stepwise assembly of complex peptides, especially those requiring precise disulfide bridge pairing. Commonly applied in solid-phase and solution-phase synthesis of therapeutic peptides and proteins. Stable under a range of reaction conditions, yet both protecting groups can be removed selectively—trityl under mild acidic conditions and Cbz via hydrogenolysis—making it valuable in multi-step synthetic strategies.