As with artificial molecular motors, there has been a surge of interest in supramolecular materials whose assembly is influenced by an ongoing chemical reaction with the ultimate aim of generating self-assembled structures in a non-equilibrium steady state. However, unlike motors, where directed molecular motion is correlated with flux through the reaction network, requiring the system to escape detailed balance, the consequences and benefits of a supramolecular material being maintained at a non-equilibrium steady state are less obvious.