<p>Hollow materials have designed with shell structures and porous cavities, as a new generation of functional materials, have shown remarkable performance in various fields. In this study, a magnetic, porous, and reusable nanocatalyst was designed and prepared. The CoNiFe₂O₄@C nanocatalyst was prepared through a multistep process. Initially, the magnetic trimetallic CoNiFe₂O₄ was prepared and followed by the deposition of a Silicon dioxide (SiO₂) layer to form the CoNiFe₂O₄@SiO₂ yolk–shell structure. The subsequent removal of the silica layer is resulted in the formation of the CoNiFe₂O₄@C yolk-shell magnetic nanocomposite. In this protocol, bisphenol derivatives were synthesized through a three-component reaction of aldehyde and 2–4-dimethylphenol in a ratio of 1:2 by using this prepared catalyst. The applications of bisphenols are included antioxidant, anticancer, anti-arthrosis, anti-inflammatory and antimicrobial properties. The identification of the prepared catalyst was carried out and reported using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Energy-dispersive X-ray spectroscopy (EDS), Mapping, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) techniques. Also, the bisphenol products were identified using melting point, FT-IR, proton nuclear magnetic resonance (¹H NMR) and carbon-13 nuclear magnetic resonance (¹³C NMR) analyses. The proposed approach presents multiple benefits such as; mild reaction conditions, ease of operation, reliable safety, excellent yield, effective purification of synthetic organic compounds, and minimal catalyst usage.</p>