The synthesis of complex and highly functionalised peptides remains a significant challenge, particularly when non-canonical modifications such as sulfation are required. My research focuses on developing synthetic technologies that expand the chemical toolbox for peptide construction, integrating advances in late-stage functionalisation, total synthesis strategies, and continuous-flow peptide assembly. As a demonstration of these technologies, we targeted the diatom sex-inducing pheromone SIP+, a recently discovered signalling molecule that contains a rare sulfated aspartic acid residue and plays a key role in regulating reproduction in marine diatom populations.1 We report the first total synthesis of SIP+ using complementary modular strategies, including the development of a sulfated building block approach alongside a solid-phase peptide synthesis (SPPS)-compatible late-stage sulfation protocol.2 These approaches provide streamlined access to the natural product and enable the preparation of structural analogues for biological investigation. To support the preparation of complex, highly functionalised peptides such as SIP+, we have also developed a practical and accessible continuous-flow SPPS platform.3 By retrofitting standard HPLC hardware with a custom reaction chamber compatible with commercially available fritted syringes, this low-cost system enables rapid peptide assembly and diverse on-resin transformations, including sulfation, deallylation, and macrocyclisation. Collectively, these advances highlight how new synthetic technologies can streamline access to chemically complex peptides and accelerate investigations across chemical biology and natural product synthesis.