Various embodiments of the present disclosure pertain to methods of making magnetic carbon nanoribbons. Such methods generally include: (1) forming carbon nanoribbons by splitting carbon nanomaterials; and (2) associating graphene nanoribbons with magnetic materials, precursors of magnetic materials, or combinations thereof. Further embodiments of the present disclosure also include a step of reducing the precursors of magnetic materials to magnetic materials. In various embodiments, the associating occurs before, during or after the splitting of the carbon nanomaterials. In some embodiments, the methods of the present disclosure further comprise a step of (3) functionalizing the carbon nanoribbons with functionalizing agents. In more specific embodiments, the functionalizing occurs in situ during the splitting of carbon nanomaterials. In further embodiments, the carbon nanoribbons are edge-functionalized. Additional embodiments of the present disclosure pertain to magnetic carbon nanoribbon compositions that were formed in accordance with the methods of the present disclosure.