Ammonium tetrachloropalladate(II) is primarily used in the field of catalysis, where it serves as a precursor for various palladium-catalyzed reactions. It is particularly valuable in organic synthesis for processes such as cross-coupling reactions, including the Heck, Suzuki, and Sonogashira reactions, which are essential for forming carbon-carbon bonds in the production of pharmaceuticals, agrochemicals, and fine chemicals. Additionally, it is employed in the preparation of palladium nanoparticles and thin films, which are utilized in electronics and sensor technologies. It is also used in metal plating processes to enhance the durability and aesthetic appeal of workpieces. Its role in analytical chemistry includes use as a reagent for the detection and quantification of specific compounds.