The use of neopentylphosphine ligands in the palladium-catalyzed Suzuki, Sonogashira, Heck, and Hartwig–Buchwald couplings of aryl bromides and chlorides are reported. Di-tert-butylneopentylphosphine (DTBNpP) provided highly active catalysts for the coupling of aryl bromides at mild temperatures. Trineopentylphosphine, an air-stable trialkylphosphine, gave inactive catalysts at room temperature, but showed good activity in the H–B amination of aryl chlorides at elevated temperatures.