In this study, a magnetic and heterogeneous nanocatalyst based on in situ synthesis of CuFe₂O₄ supported on mesoporous graphitic carbon nitride (mpg-C₃N₄) was developed. This mesoporous nanocomposite was well characterized via standard analysis methods. This catalyst was applied under simple and ligand-free condition in Ullmann-type arylation reaction to afford a vast variety of target o-arylated products in satisfactory yields. It should be noted that working under an inert atmosphere was not required for this coupling reaction. The control experiment showed that mpg-C₃N₄ was a key factor to proceed the reaction and the XPS analysis confirmed this role. Moreover, owing to stability and magnetically separatability of CuFe₂O₄/g-C₃N₄, this nanocomposite could be easily separated by an external magnet and reused for five cycles without loss of its high activities during cycles.