7-Iodo-8-hydroxyquinoline-5-sulfonic acid (Ferron, HIQSA, Chiniofon) is a multifunctional chelating agent whose utility is significantly enhanced through immobilization onto solid supports. This comprehensive review details the chemical structure and key properties of Ferron, emphasizing it’s tridentate chelating ability derived from its hydroxyl, sulfonic acid, and iodine functional groups. The primary rationale for immobilization—improved reusability, enhanced stability, facilitated separation, and the enablement of solid-phase ap...plications—is thoroughly discussed. The review systematically examines the three main immobilization strategies: covalent bonding (e.g., using silane coupling agents on silica or functionalized polymers), physical adsorption (e.g., on anion-exchange resins like Dowex and Purolite), and encapsulation/entrapment (e.g., in sol-gel matrices or electrospun polymer nanofibers). Each technique's principles, advantages, disadvantages, and typical supports are analyzed. The diverse applications of immobilized Ferron are then explored, spanning analytical chemistry (optical oxygen and metal ion sensors, electrochemical detection, flow injection analysis), environmental remediation (heavy metal removal from wastewater, soil stabilization), and emerging biomedical uses (antimicrobial wound dressings, drug delivery scaffolds). The article concludes with a historical perspective and an outlook on recent advancements, highlighting the potential of nanomaterial-based supports, multi-functional hybrid platforms, and novel biomedical applications, while also addressing ongoing challenges such as long-term stability and selectivity.Read more