NanoLuc® Binary Technology (NanoBiT®), a two-part complementation system based on NanoLuc luciferase, is a proven technology for analyzing proteins at a cellular level. NanoBiT is comprised of an 11-amino acid subunit (low-affinity SmBiT or high-affinity HiBiT) that binds to its cognate large subunit partner (LgBiT) to form a bright luciferase that produces light when furimazine is added. We are building NanoBiT proximity immunoassays where complementary antibodies (or other affinity reagents) are labeled with NanoBiT subunits such that binding to analyte brings SmBiT and LgBiT into proximity, thereby producing signal proportional to analyte levels. This homogeneous detection chemistry has several advantages, including simple, add-and-read protocols, no requirement for sample transfer, no washes, and a broad linear dynamic range mitigating the need for sample dilutions. Moreover, time to assay completion is <30 to < 90 minutes, depending on the specific assay. In development are assays for detection of cytokines (e.g., IL-1β), metabolic targets (e.g., Insulin), FcRn binding, cellular pathway analyses (total and phospho-protein levels), as well as labeling kits to build your own Lumit immunoassays.