"The TOPCHEM project investigates an innovative approach to the on-surface synthesis of molecular products by performing chemical reactions within geometrically well-defined 2D regions on a substrate. The size and shape of these regions is governed by the dimensions of a porous molecular template adsorbed on the surface, formed by the self-assembly of hydrogen-bonded or covalently linked molecular architectures. The ‘topochemical’ reactions carried out within these pores may be driven along a specific reactions pathway towards a desired chemical product by utilising the size- and shape-confinement offered by the molecular template. This novel methodology for the control of chemical reactions by defining the number and geometric arrangement of reactant species within a pore has the potential to facilitate multi-component reactions, allowing an alternative route for the synthesis of complex molecules.Scanning probe techniques (Scanning Tunnelling Microscopy (STM) and non-contact Atomic Force Microscopy (nc-AFM)) will be used as the primary tools for characterising the self-assembled molecular templates, as well as the reactant and product molecules. The sub-molecular resolution offered by nc-AFM will enable the identification of the structure of the product molecules, with characterisation on the level of single chemical bonds. Additional chemical information about the molecular systems will be obtained using a combination of photoelectron spectroscopy (PES) and secondary ion mass spectrometry (SIMS)."