The syntheses and properties of two novel [Ru(bpy)2(L−L′)]n+ complexes with L−L′ = 3-carboxy-5-(pyrid-2′-yl)-1,2,4triazole (H2cpt) or 3-(ethoxycarbonyl)-5-(pyrid-2′-yl)-1,2,4-triazole (Hcept) ligands are described. Previous publications on RuII complexes containing (pyrid-2′-yl)-1,2,4-triazoles revealed that their coordination is possible via N1 and N4 of the triazole ring. 1H NMR spectroscopic data and the crystal structure of [Ru(bpy)2(cept)]PF6·H2O (2) indicate that the coordination of the Hcpt− and cept− occurs via N1 of the triazole ring. The crystals of 2 are monoclinic and belong to the space group P21/n with a = 12.339(7), b = 16.512(7), c = 16.802(8) A, β = 110.29(4)°, and Z = 4. A water molecule is hydrogen-bonded to the carbonyl oxygen atom of the ethoxycarbonyl group with an O···O distance of 2.891 A. Spectroscopic measurements reveal that H2cpt and Hcept are strong σ-donor ligands. When coordinated to a ruthenium(II) centre, both triazole ligands reported in this study lost their acidic triazole hydrogen atoms and became negatively charged, resulting in even stronger σ-donor ligands, as demonstrated by a negative shift of their redox potentials compared to the complexes containing the neutral ligand. The complexes reported in this study showed 3MLCT-based luminescence emission, both at room temperature and at 77 K. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)