This study successfully utilized the Mn (III)–porphyrin complex (Mn (PT)Cl) as an efficient and recyclable catalyst for a one‐pot, three‐component reaction involving aromatic aldehydes, 2,4‐thiazolidinedione, and thiourea. The reaction yielded thioxo‐4,5‐dihydro‐3H‐thiazolo pyrimidin‐2‐one derivatives under eco‐friendly conditions. Elemental and spectral analyses confirmed the structures of the synthesized compounds, validating the successful formation of the target products. The reactions were conducted in a sustainable environment using a green solvent mixture of H₂O and EtOH. The results showcased the excellent catalytic activity and selectivity of the complexes, resulting in good yields of the desired products. This research provides valuable insights into the synthetic applications of the Mn (PT)Cl complex and emphasizes the potential of such catalysts for various organic transformations. The method's simplicity, safety, commercial availability, stability, rapid reaction times, and high yields indicate promising future applications in industry.