The reaction of two equivalents of [Co(PMe3)4] (1) with one equivalent of a neutral NNO pincer ligand (L1) led to the formation of purple-coloured single crystals. The crystal structure determination reveals the molecular structure as a cobalt dimer [Co2(L1)(PMe3)5], which is solved in the triclinic P1[combining macron] space group. Although this species appears to have a formal zero oxidation state on cobalt ions, careful analysis of the structural parameters of the L1 reveals that the NNO ligand is reduced by three electrons; this observation has rarely been reported in the literature. Therefore, herein, more accurate description of the molecular formula [(PMe3)2CoII(η4-L13-)CoI(PMe3)3] (2) was proposed. In 2, we observed an unusual η3-π-allyl-type binding mode of the pyridine ring carbon atoms of the L13- ligand with the cobalt ion. X-ray photoelectron spectroscopy not only reveals the presence of the mixed valent cobalt ion within 2 but also unambiguously discloses the spin state of these metal ions (Co(i) diamagnetic (low-spin) and Co(ii) paramagnetic (high-spin)). The proposed electronic structure is consistent with the magnetic moment measured at room temperature. The electronic structure of 2 was further supported by the Q-band EPR measurements performed on polycrystalline sample of 2 at 5.0 K, and the presence of two independent S = ½ states was revealed. This has been qualitatively rationalized based on the super-exchange coupling pathway observed in 2. The NMR studies performed for 2 (C6D6 solvent) evidently showed that the solid-state structure of 2 was maintained in solution.