<p>A thermo-responsive ruthenium catalyst was developed by grafting poly (<i>N</i>-isopropyl acrylamide) on silica-modified iron oxide nanoparticle core–shell (Fe₃O₄@Si) through free-radical polymerization process. The amino-functionalized support was obtained by exposing it to ethylenediamine. Further, the as-prepared compound was treated with ethylenediaminetetraacetic acid (EDTA), followed by embellishment with Ru NPs to form a well-organized heterogeneous catalytic structure (Fe₃O₄@Si-modified PNIPAAm-Ru). This unique system exhibits several remarkable features, including a broad distribution of catalytic sites, exceptional thermal stability, and the utilization of environmentally friendly solvents. Additionally, it offers significant features like easy separation and recyclability of the catalyst waste. Various characterization methods proved catalyst structure properly. The catalyst demonstrated a remarkable role in the carbon–carbon cross-coupling transformations of Sonogashira-Hagihara, Suzuki–Miyaura, and Mizoroki–Heck using different aryl halides under TBAB, copper, and amine-free conditions. One key advantage of this catalytic system is its ability to be reused for a minimum of 8 repetitions without any considerable decline in activity, structural changes, or leaching.</p>