This article presents a combined experimental and computational study of Ru(II) complex containing 2,5-pyridinedicarboxylic acid ligand. The novel complex [Ru(py-2,5-COOH)2(PPh3)2]·3H2O has been obtained in the reaction of [RuCl2(PPh3)3] with 2,5-pyridinedicarboxylic acid in methanol and has been studied by IR, 1H, 31P NMR, UV–Vis spectroscopy, and X-ray crystallography. The electronic structure of [Ru(py-2,5-COOH)2(PPh3)2] has been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of the complex have been calculated with the time-dependent DFT method, and the UV–Vis spectrum has been discussed on this basis and rationalized by determination of ligand field splitting (10Dq) and Racah’s parameters from the experimental spectrum. The luminescence property of the complex has been examined.