Part I Based on mechanism-driven reaction design, a Pd-catalyzed nucleophilic fluorination of aryl bromides and iodides has been developed. The method exhibits a broad substrate scope, especially with respect to nitrogen-containing heteroaryl bromides. The use of Pd(0) species [L•Pd(1,5-cyclooctadiene)Pd•L] (L = Ad₂ArP) as a precatalyst, a facilitated ligand modification process, and an additive effect of KF was shown to be critical to the success of the reaction. Part II The Pd-catalyzed cross-coupling reactions have been applied to synthesize radiotracers for positron emission tomography and bioconjugates. The enabling technology has successfully mediated C–C and C–N bond-forming reactions under highly specialized settings. Key to the success was the easy and expeditious preparation of the stable oxidative addition complexes, which has greatly simplified the overall process.