“…In contrast to homogeneous catalysts, Cu-based heterogeneous catalysts are more attractive from the viewpoint of sustainable chemistry owing to their recyclability. The reported heterogeneous Cu catalysts with O 2 as the oxidant for the coupling generally involve nano-Cu 2 O, Cu nanotubes, Cu–Cu 2 O–C nanocomposites, Cu/TiO 2 , Cu/SiO 2 , Cu-doped TiO 2 , Cu(OH) x /TiO 2 , Cu(OH) x /OMSs (OMS, manganese oxide-based octahedral molecular sieve), Cu–Al layered double hydroxides (CuAl–LDHs), Cu-based metal–organic frameworks, , NHC–Cu complexes immobilized on carbon materials, and various heterogenized Cu salts. − …”