Welcome to the timely publication of this chapter entitled: Molecularly Imprinted Catalysts. Principles, Synthesis and Applications. In many cases, molecular imprinting is associated with:Existing applications such as selective adsorbent, separation and solid phase mining. In fact, the latter has had many commercial successes. Products available on the market. The next wave of molecular-based products. A molecularly imprinted polymer (MIP) is a polymer that has been processed using the molecular imprinting technique which leaves cavities in the polymer matrix with an affinity for a chosen "template" molecule. The process usually involves initiating the polymerization of monomers in the presence of a template molecule that is extracted afterwards, leaving behind complementary cavities. These polymers have affinity for the original molecule and have been used in applications such as chemical separations, catalysis, or molecular sensors.Molecular imprinting is the process of generating an impression within a solid or a gel, the size, shape and charge distribution of which corresponds to a template molecule (typically present during polymerization).