Chemical oxidation and oxygenation of carbonyl ruthenium(II) azuliporphyrin [Ru(TPAP)(CO)] were explored. [Ru(TPAP)(CO)] reacts with dioxygen giving carbonyl ruthenium(II) 21-oxyazuliporphyrin [Ru(TPAP-O)(CO)] revealing the activation the Ru-C bond inside azuliporphyrin coordination cavity. Solution and X-ray structural studies confirmed the tendency of [Ru(TPAP-O)(CO)] to form dimeric [Ru(TPAP-O)(CO)](2). The dimer adopts a head-to-tail structure with the azulenolate groups forming bridges from one macrocycle to the ruthenium(II) in the adjacent unit. One-electron oxidation of [Ru(TPAP)(CO)] gives the first x-cation radical of metallo-carbaporphyrinoid-[Ru(TPAP)(CO)](+center dot) with extraordinary participation of the azulene unit in the spin delocalization. The most characteristic H-1 NMR features of the radical are large, sign-alternating isotropic shifts of resonances assigned to meso-aryl, azulene, and pyrrolic hydrogen atoms. The spin distribution determined by density functional theory confirmed the pi-cation radical electronic structure reproducing the diagnostic spectroscopic features including pi-delocalization at meso-aryl resonances and very characteristic sign alternation of contact shifts for an azulene moiety.