The appearance and rapid development of bioluminescent optogenetics (BL-OG), founded on its use of endogenous, biological light as an alternative to physical external light, has elicited many research questions in a nascent field, from the physical nature of its mechanism to its therapeutic potential. One of these, the question regarding the possibility of opsin activation on one cell by bioluminescence emitted at a distance, on a different cell, signals an even newer direction: Inter-luminescence.