A novel photocatalyst iron(II) tetrahydoxymethyl-tetra(1,4-dithiin) porphyrazine (abbreviated as FePz(hmdtn) 4 ) has been successfully synthesized by template method. The prepared FePz(hmdtn) 4 ) was further characterized by UV–vis, FT-IR, 1 H NMR, LC–MS, XPS. FePz(hmdtn) 4 supported on an Amberlite CG-400 resin was used as a biomimetic catalyst for the activation of molecular oxygen with visible light to degrade a probe dye compound Rhodamine B (RhB) in aqueous solution with the degradation yield in 79% for 24 h. By means of cyclic voltammetry, the E HOMO and the Δ E HOMO–LUMO were obtained by comparing the CV and DPV spectra of the metal-free compound with FePz(hmdtn) 4 , which indicated the central Fe 2+ showed strong electron donating property for activating molecular oxygen to degrade organic pollutants. The electrochemical results were further verified by the quantum chemical DPT calculation.