The objective of this project is to develop a new family of click chemistry reactions, termed Sulfur(VI) Fluoride Exchange (SuFEx) processes, and to utilize them in biological research. SuFEx relies on readily available materials and simple transformations to produce diverse chemical structures bearing the SVI-F motif, such as OSO2F (fluorosulfate) and SO2F (sulfonyl fluoride). New molecules originating from this chemistry will be used to develop probes functionalized with the 18FO2SO radiotracer for positron emission tomography. Small- molecule screening libraries will be constructed using this methodology to identify active compounds that perturb specific pathways in zebrafish embryogenesis.