This protected dipeptide building block, Fmoc-Trp(Boc)-Thr(psi(Me,Me)pro)-OH, is utilized in solid-phase peptide synthesis (SPPS) to introduce a tryptophan-threonine sequence with enhanced solubility and reduced aggregation. The Fmoc group protects the α-amino group of tryptophan, while the Boc group safeguards the indole nitrogen of the tryptophan side chain. The ψ(Me,Me)Pro modification on threonine acts as a pseudoproline dipeptide, promoting better folding control and stability during synthesis. It is essential for producing therapeutic peptides, peptide-based drugs, and research peptides requiring precise sequence integrity. Additionally, it supports studies on peptide folding, stability, and protein interactions, advancing biochemistry and drug discovery.