Co-MTL@M catalyst was synthesized by immobilizing cobalt nanoparticles on magnetic nanoparticles Fe3O4 coated with mannitol (MTL) and characterized by SEM, FT-IR, TEM, VSM, XRD, ICP, TGA analyzes. The fabricated catalyst was used as a catalyst for the bonding of carbon and nitrogen to substrates with different functional groups under mild and stable conditions.Mannitol was used instead of the common metal carrier coating agents. Hydroxy-groups on MTL enable to modulation of cobalt coordination. This catalyst efficiently promotes carbon-nitrogen cross-coupling of a large library of functional substrates under mild and sustainable conditions Looking for an alternative to common organic solvents that have environmental, health, and safety problems. We utilized bio-based solvent ?-Valerolactone (GVL) for coupling reactions of aryl halides and secondary (hetero) amines in room temperature. The cobalt complex also provides intermediate to good yields in Sonogashira cross-reactions as an efficient, inexpensive, and green heterogeneous catalyst. Also this catalyst is stable under the reaction conditions and can be reused easily five successive runs without a discernible decrease in its catalytic activity.