Novel theranostic tool based of nitrogen-doped carbon dots and ferrite nanoparticles is reported. CDs are sp2 or sp3 hybridized carbon-based particles with sizes in the range of 1-10 nm. The properties that can be used in the medical field are their biocompatibility, high functionalizability, solubility in water, photoluminescence and ease of preparation. FNPs of zinc , nickel, zinc-nickel and bismuth are also prepared. Their properties include cytotoxicity, magnetism, ease of preparation. A simple and effective protocol of conjugation between CDs and FNPs is proposed. CDs-FNPs conjugates are good candidates for imaging and tumor treatment applications such as localized phototherapy, hyperthermia and chemotherapy.