Magnetic-organic core-shell nanoconstructs, which integrate therapeutic and diagnostic functions onto a sole platform, provide a revolutionary approach to cancer theranostics. These nanoparticles, which have an organic shell for improved biocompatibility and targeted drug delivery and a magnetic core for enhanced imaging capabilities, have shown significant potential to improve treatment precision through real-time therapeutic efficacy monitoring while minimizing systemic toxicity. Their synthesis involves a variety of techniques that could be tuned at one end to attain important properties such as size and surface charge and, on the other end, functionalization for efficient tumor targeting and drug release. Different magnetic core materials like metals and their oxides offer unique properties for imaging (e.g., MRI) and treatment applications (e.g., hyperthermia). Surface functionalization for the attachment of targeting ligands that enhance delivery specificity complements the enhanced stability and functionality conferred by the organic shell materials. In such a way, nanoconstructs are a hybrid material that already suggests many different applications—from chemotherapeutic, phototherapeutic, and ultrasound-responsive strategies—the promise they hold in revolutionizing both cancer diagnosis and therapy through new design and synthesis methods.