The complexes RuCl 2 (L 1 )(arene) (3-4) (L1=HC NCH 2 CH 2 NR, R=Et, arene=p-MeC 6 H 4 CHMe 2 or C 6 Me 6 ) and RuCl 2 (L 2 )(arene) (5-6) (L 2 =HC NCH 2 CH 2 CH 2 NR, R=Me, Ph, CH 2 Ph, p-MeC 6 H 4 ) have been synthesized by reaction of [RuCl 2 (arene)] 2 with 1-alkyl-2-imidazoline (1) or 1-alkyl-1,4,5,6-tetrahydropyrimidine (2). In each of these complexes (3-6) the ligand is bound via the imine (N C) nitrogen atom. The new complexes are capable of catalyzing the activation of (Z)-3-methylpent-2-en-4-yn-1-ol into 2,3-dimethylfuran in very good yield, via intramolecular cyclization, and the 1,4,5,6-tetrahydropyrimidine complexes 5 and 6 appeared to be the best catalyst precursors. Cyclic voltammetry shows that the nature of the arene ligand, rather than that of the nitrogen containing ligand, controls the electron-richness of the complexes.