Functionalized magnetic nanomaterial (FMNs)Functionalized Magnetic Nanomaterials (FMNs)-based photocatalysts have drawn a lot of interest because of their advantages, which include simple recyclingRecycling characteristics and easy catalyst recovery, which match material research and photocatalytic processes to the needs of a greener economy. Functionalized nanomaterialsNanomaterials(FMNsFunctionalized Magnetic Nanomaterials (FMNs)) are essential for and provide novel approaches to environmental remediationEnvironmental remediation through photocatalytic degradationPhotocatalytic degradation, especially when it comes to breaking down organic pollutantsOrganic pollutants and air and water pollutants. These materials are very effective at converting toxic compounds into safe byproducts like CO2 and H2O because they blend nanoscale characteristics with tailored surface functions to increase photocatalytic performance under light irradiation. The breakdown of organic molecules by visible and ultraviolet light has been a common use for photocatalysts. Various synthesis methods have been created and refined to create effective, affordable, and environmentally acceptable materials for photo-treating water samples polluted with dyes, pigments, pesticidesPesticides, and other organic contaminants. Some examples of FMNsFunctionalized Magnetic Nanomaterials (FMNs) in photocatalysisPhotocatalysis include TiO2-based, ZnO, and graphitic carbon nitride (g-C3N4)-based nanomaterialsNanomaterials. Magnetic materials have become a viable substitute in the past 20 years for facilitating catalyst isolation in liquid-phase reactions that are heterogeneously catalyzed. The primary synthesis procedures and novel protocol changes for the production of magnetic photocatalystsMagnetic photocatalysts, as well as their effects on catalyst morphology, efficiency, and recyclingRecycling, are the key topics of discussion in this chapter, among other works. Although FMNsFunctionalized Magnetic Nanomaterials (FMNs) show great potential in photocatalytic degradationPhotocatalytic degradation, scaling up, stability, and avoiding nanoparticleNanoparticles aggregation are still difficult tasks. To overcome these constraints, research is concentrated on creating hybrid materials, improving functionalizationFunctionalization strategies, and investigating sustainable synthesis approaches.