The aryl fluoride motif is a mainstay in a variety of disciplines, most notably pharmaceuticals, agrochemicals, and in positron emission tomography (PET). A large number of clinically approved pharmaceuticals contain this substituent due to its importance in tailoring the properties of organic molecules. [1] While numerous methods have been developed to construct aromatic C À F bonds, most, if not all, suffer from at least one drawback with regard to safety, practicality, and/or substrate scope. [2] Recently, there has been an increase in the number of new methods, particularly in the use of metal-catalyzed or -mediated processes. In particular, work by the groups of Grushin, [3] Sanford, [4] Ritter, [5] Yu, [6] and others [7] have both increased the number of synthetically useful aryl C À F bondforming reactions as well as deepened our understanding of the underlying challenges inherent in such processes. The state of the art of these methodologies, however, are far from ideal especially when compared to other aryl carbonheteroatom bond forming reactions. [8] We recently described the catalytic conversion of aryl triflates to aryl fluorides using CsF as the fluoride source and a Pd-catalyst based on tBuBrettPhos (1). [9] This fluorination reaction utilized readily available "F À " sources as the fluorine atom donor. Owing to the exceedingly low solubility of anhydrous CsF in the nonpolar solvents typically employed for this transformation (e.g., toluene, cyclohexane) the reaction is visibly saturated with fluoride, yet increasing the amount of CsF increases the rate of CÀF bond formation (Figure 1). [10] While short reaction times can be attained using large excesses of CsF, the amount of