RFID a little too bulky and cumbersome for your needs? Need a technology that performs a similar function, but at a molecular level? Need to keep an inventory of your collection of nanomachines or engineered cells? Fear not! Molecular Computational Identification (MCID) could be the answer to your problems – using tiny molecules capable of performing logic functions in response to the presence of certain chemicals could be the early stages of computing without electricity or magnetism, as well as a revolution for medical science.