Palladium ions were successfully immobilized within the pores of open metal site (OMS) metal organic frameworks (MOFs) with Schiff‐base (2‐Py‐SI) grafted in OMS‐Cu (BDC) using the hydrothermal method. This Schiff‐base complex on the Cu (BDC) greatly increased catalytic activity and acted as an efficient stabilizer of Pd ions. The hydrothermal method was a more efficient method for generating small metal ions in the MOF structures. The results revealed that the PdII@Cu (BDC)/2‐Py‐SI is a promising catalyst for the Mizoroki‐Heck coupling reaction. The proposed catalyst has better recyclability and can be reused several times without apparent loss of activity.