Cell-free expression (CFE) is a highly versatile tool used to achieve rapid RNA/protein synthesis through in vitro transcription and translation (IVTT) of natural or synthetic DNA. Avoiding cell-based synthetic biology limitations, such as laborious genetic encoding, gene delivery and slow design-build-test cycles, 2 CFE is ideal for high-throughput drug screening, the study of biological processes, gene circuits, and the purification of proteins otherwise challenging to express (e.g., containing non-natural amino acids). As a result, CFE technologies have recently gained great interest from the biomanufacturing field and industry. Moreover, CFE mixtures can be encapsulated in lipid bilayers to form synthetic cells for applications in drug delivery and studying cellular communication. The ability to control the function of these cell-free systems will be a key step to advance this technology towards more complex gene circuits or in situ formation and release of therapeutics. Control can be achieved with molecular inputs for RNA switches and transcription factor-based biosensors, with the analyte being the trigger for CFE activation. However, these signal molecules can be difficult to apply as, when added at different timepoints, they will change the concentrations of the components and are mostly not applicable for encapsulated systems such as synthetic cells. Furthermore, most of these molecular systems have been optimised for use in living cells and do not show optimal activity in cell-free systems. Light, on the other hand, is an ideal stimulus for controlling cell-free system systems as it can be applied remotely to closed systems in a spatiotemporal manner, has low toxicity, and is bioorthogonal to most biological processes. Furthermore, unlike other remote stimuli, it is possible to use multiple, orthogonal wavelengths of light to control different biological processes in the same system, opening up the prospect of precise, remotecontrol of cell-free systems.