Solid phase synthesis is a method in which the initial substrate is covalently attached through a cleavable linker to an insoluble polymeric or inorganic support, and subsequent transformations are performed on the support-bound intermediate. Reagents are normally supplied in solution and may be used in excess; after each reaction, unconsumed reagents and soluble by-products are removed by filtration and washing rather than by isolating the growing molecule ^[1]. A complete cycle therefore comprises support loading, reaction, washing, and, when required, temporary protecting-group removal, followed eventually by cleavage from the support. Merrifield peptide synthesis established the defining iterative form of the method, while solid-phase organic synthesis extends the same support-and-linker logic beyond peptides ^[2]. The concept excludes simple heterogeneous catalysis because the product-forming substrate, not merely a catalyst, is immobilized, and it excludes adsorption without a designed covalent attachment and cleavage strategy.