Flavonoids are natural substances that we can find in various plant species, and they are recognized for their different phenolic structures. These substances hold quite a few properties for health promotion, disease prevention, and well-being. Flavonoids have caught the eye of researchers, primarily because of their strong interaction with biology. Their antioxidative potential is remarkable experimental studies, and they have been reported to stimulate the body’s own enzyme defenses. Flavonoids have been recognized as anti-cancer agents, displaying chemopreventive and antiproliferative effects on cancer cells. Furthermore, they are effective in reducing inflammation, curbing angiogenesis, and blocking metastases of cancer. Despite their biological promise, many flavonoids suffer from low water solubility and limited bioavailability, so they are being incorporated in nanocarriers to improve their therapeutic performance. The production of noble metal nanoparticles through chemical reduction methods has attracted great interest because of their useful physical, chemical, and biological properties. Metallic nanoparticles are increasingly becoming attractive for drug delivery as they can act simultaneously as diagnosis and treatment (theranostics) agents. This chapter discusses the structural characterization and targeted applications of metal–flavonoid complexes. Flavonoids in combination with metal ions hold the possibility to enhance bioavailability and better targeted release. Metal nanoparticles deliver these complexes to specific sites, enhancing their therapeutic effects, particularly in cancer and inflammatory diseases, while minimizing side effects. In conclusion, metal flavonoids incorporated into advanced drug delivery systems, including ligand-based nanoparticles, stimuli-responsive carriers, and hybrid nanostructure flavonoid–metal complexes, exhibit the potential to attain greater than ever targeted delivery parameters, improved cellular uptake, and reduced systemic toxicity.