A family of Cu(I) complexes [Cu(L^1–4)(Cl)(PPh₃)] (C1–C4) were synthesized from bidentate ligands L¹–L⁴ (where L¹ = (E)-2-(2-benzylidene-1-phenylhydrazinyl)pyridine, L² = (E)-N,N-dimethyl-4-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)aniline, L³ = (E)-2-(2-(4-chlorobenzylidene)-1-phenylhydrazinyl)pyridine and L⁴ = (E)-2-(2-(4-nitrobenzylidene)-1-phenylhydrazinyl)pyridine) and characterized. The structure of complex C1 was authenticated by single-crystal X-ray diffraction. These complexes were utilised as catalysts for N-arylation of benzimidazoles and indoles. The effect of the substituents in the ligand frame of metal complexes were examined and the probable reaction pathway was scrutinized.