The ruthenium-nitrido POM derivative [PW11O39{(RuN)-N-VI}](4-) has been synthesized by reaction between [PW11O39](7-) and [(RuNCl5)-N-VI](2-) or [(RuNCl4)-N-VI](-). Its molecular structure has been confirmed from multinuclear P-31 and W-183 NMR spectroscopy together with an EXAFS study, while the oxidation state of the ruthenium bearing the nitrido ligand has been inferred both from W-183 NMR and XANES analysis at the Ru-K edge. The potential of [PW11O39{(RuN)-N-VI}](4-) in N-atom transfer reactions has been demonstrated through reaction with triphenylphosphine, which ultimately leads to the release of the bis(triphenylphosphane)iminium cation [PPh3NPPh3](+) through several intermediates, among which the phosphoraniminato derivative [PW11O39{(RuNPh3)-N-V}](3-) has been structurally characterized. Its unusual oxidation state is in accordance with its EPR spectrum.