Here, we synthesized new thiazole complexes from Cu (II), Fe (III), and Pd (II) ions. Such complexes were characterized to present their chemical formulae, firstly. The octahedral geometry was suggested for the investigated complexes except Pd (II) complex (ARPTPd), which has a square‐planer arrangement. ARPTPd was planned to be used as a catalyst for synthesis of dihydrotetrazolo[1,5‐a]pyrimidine derivatives at mild conditions. The catalytic activity of ARPTPd complex in four‐components reaction approach was deliberately monitored till it reaches the most favorable conditions. The advantages of suggested catalyst were basically summarized by using green solvent (H₂O), lower reaction time, and high products yields. Also, the superiority of ARPTPd complex and ultrasonic irradiation towards synthesis of dihydrotetrazolo[1,5‐a]pyrimidine derivatives was revealed compared with other Lewis acids, basic, and ionic liquid catalysts. Furthermore, the mildness of conversion and compatibility with different functional groups makes it attractive. In addition, in consecration, computational aspects were often taken according to their effect on the declaration or discrimination of variable functional characteristics. Crystal packing systems of complexes were configured to extract important surface properties. DFT study was also applied to explain the causes behind the superiorly of ARPTPd complex. Also, the optimization process for intermediates was executed to support the suggested mechanism. Finally, this simple, economical, and green catalytic procedure may be applied to the industry in future.