In this article, the direct N-alkylation reactions of amines with alcohol derivatives using the borrowing hydrogen methodology have been investigated. For this purpose, a new series of half-sandwich ruthenium(II) complexes bearing N-coordinated benzimidazole complexes have been synthesized and fully characterized by FT-IR, ¹H NMR and ¹³C NMR spectroscopies. Additionally, the structures of the complexes 2a–2e have been characterized by X-ray crystallography. All new complexes were investigated for their catalytic activities in the alkylation reaction of amines with alcohol derivatives. It was found that alkylation reactions in a solvent-free medium are efficient and selective.