The control of a solid-state polymerisation reaction using hydrogen-bonding to direct crystal packing has been attempted. The chemical reaction is the 2+2 photocycloaddition of olefin groups of amide derivatives of p-phenelenediacrylic acid. In single crystals, hydrogen-bonds organise these molecules in two-dimesional ’ribbon’, ’sheet’ or ’tape’ networks. No reaction has been observed between molecules within these networks. However when the molecules adopt a planar conformation the networks pack together such that cycloaddition can take place between molecules in adjacent networks.