The computational study of reactions either organic or inorganic is a most important tool, alongside as experimental tools. The motivation of the DFT study for chemical reactions is finding exact mechanism or scheme for developing other reactions without the cost of chemicals as well as reduces the laboratory timings. Mainly the transition metals (TM) are playing major roles in organic synthesis since the 1960s. Among the number of transition metals, the center of attraction and game changer in coupling reactions is Palladium (Pd). Heck reaction