In this thesis, chitosan core- shell magnetic nanoparticles were prepared and functionalized with methyl salicylate ligand and cobalt nanoparticles immobilized on the surface of these particles. The Catalyst was characterized by using ICP, XRD, SEM-EDX, VSM, FT-IR, SEM and TEM analyses. Catalyst magnetic properties by VSM techniques was confirmed. Presence of cobalt was evaluated by ICP and SEM-EDX techniques. XRD technique was used to prove the magnetic phase and Co (II). TEM and SEM techniques were used to demonstrate the nanoscale catalyst. Performance of M NPs @Cs-Ms-Co catalysts in the C-C coupling reactions was studied. The prepared catalyst was extracted simply at the end of each reaction by using centrifuge apparatus and the external magnetic field and reused.