Molecularly imprinted polymers (MIPs) are ‘smart materials' polymerised in the presence of a template molecule, of which they retain a chemical ‘memory'. When the template molecule is extracted from the polymer, it leaves behind cavities that are complementary to it, thus making the material capable of rebinding that molecule with high affinity and selectivity. Such materials, imprinted both with small molecule and with protein templates, have been used in chromatographic, chemical, and biological sensing applications. Here, we review a variety of uses for MIPs, focusing on their recently discovered role as nucleation inducing substances for protein crystals. This discovery makes them useful tailor-made ‘nucleants' to be used both for optimisation of protein crystal growth and for discovering new crystallization conditions.