Abstarct: In the first part, Fe3O4-Ag@OPO(OH)2 nanocomposite was prepared using Camellia sinensis leaf extract. This plant extract was used to reduce silver ions to silver nanoparticles in a magnetite bed. The change in color of the solution from light to dark, along with a new absorption band at a wavelength of λmax = 410 nm, confirms the deposition of silver nanoparticles on the surface of magnetite. X-ray diffraction analysis (XRD) was used to identify silver and magnetite phases and calculate the average size of crystallite (21 nm). The FT-IR (Fourier transform infrared) spectrum of the as-synthesized nanocomposite showed the vibrational bands of functional groups of flavonoids and other phenolic compounds on its surface. Energy dispersive X-ray spectroscopy (EDS) of functionalized Fe3O4-Ag@OPO(OH)2 nanocomposite confirmed the presence of Ag, Fe, O and P elements in the sample. Vibrating sample magnetometer (VSM) analysis showed that the magnetic nature of Fe3O4-Ag@OPO(OH)2 functionalized nanocomposite is lower than Fe3O4 nanoparticles, which is related to the non-magnetic nature of silver nanoparticles and phosphate baxse covered on Fe3O4 surface. Functionalized Fe3O4-Ag@OPO(OH)2 nanocomposite showed high catalytic activity for the reduction of para-nitrophenol. In the second part, the magnetically recoverable compound Fe3O4-Cu@OPO(OH)2 was synthesized by a green method using Juglans regia leaf extract. This preparation method is non-toxic and safe for the environment. Phenolic compounds present in the extract are responsible for the reduction of copper (II) ions to copper nanoparticles. The innovation of the work is that by using walnut tree leaf extract, a nanocomposite containing copper nanoparticles was prepared, which acts as a good conductor for electron transfer in the photocatalytic process. The crystalline phase of Fe3O4-Cu@OPO(OH)2 nanocomposite was identified using a XRD pattern. The results of the FT-IR technique confirm the Fe-O bond in the nanocomposite and the presence of phenolic compounds in the extract. The morphology of the as-synthesized compound was identified by FE-SEM. The as-synthesized nanocomposite has elements of copper, iron, oxygen and phosphorus, and the EDX technique confirms the presence of these elements in it. The VSM curve showed that the Fe3O4-Cu@OPO(OH)2 functionalized nanocomposite has magnetic properties. The photocatalytic performance of this as-synthesized nanocomposite by an environmentally friendly method was investigated in the decolorization of methylene blue. In the absence of this functionalized nanocomposite, the measurable reduction reaction could not occur. After 4 hours of light irradiation, it was found that a significant part of the methylene blue was destroyed. The photocatalytic degradation of methylene blue by Fe3O4-Cu@OPO(OH)2 nanocomposite was 95%. Addition of copper nanoparticles on the magnetic iron oxide substrate causes easy recovery of the nanocomposite in the suspension solution related to its photocatalytic process. The photocatalytic activity kinetics of Fe3O4-Cu@OPO(OH)2 nanocomposite against methylene blue was studied using UV-Visible spectrometer, which is a pseudo-first-order reaction.