Z-Trp-Trp-OH is a protected dipeptide building block used in peptide synthesis to incorporate consecutive tryptophan (Trp-Trp) residues into larger peptide chains. The Z (benzyloxycarbonyl) protecting group on the N-terminal tryptophan enables selective coupling reactions while preventing unwanted side reactions at the amino terminus. It is commonly employed in both solid-phase and solution-phase peptide synthesis for the production of complex peptides, pharmaceuticals, and bioactive molecules where precise control over sequence and structure is essential. Additionally, it serves as a valuable tool in biochemical research to investigate tryptophan-rich peptide motifs, protein interactions, folding, and stability.