Molecular and electronic structures of Ir-2(1,8-diisocyanomenthane)(4)(n+) (Ir(dimen)(n+)) complexes have been investigated by DFT for n = 2, 1, 0 (abbreviated 2+, 1+, 0). Calculations reproduced the experimental structure of 2+, v(C N) IR, and visible absorption spectra of all three oxidation states, as well as the EPR spectrum of 1+. We have shown that the two reduction steps correspond to successive filling of the IrIr p sigma orbital. Complexes 2+ and 1+ have very similar structures with 1+ having a shorter IrIr distance. The unpaired electron density in 1+ is delocalized along the IrIr axis and over N atoms of the eight C N-ligands. The second reduction step 1+ -> 0 changes the Ir(CN-)(4) coordination geometry at each Ir site from approximately planar to seesaw whereby one -N C-Ir-C N- moiety is linear and the other bent at the Ir (137 degrees) as well as N (146 degrees) atoms. Although complex 0 is another example of a rare (ps)2 dimetallic species (after [Pt-2(mu-P2O5(BF2)(2))(4)](6-), J. Am. Chem. Soc. 2016, 138, 5699), the redistribution of lower lying occupied molecular orbitals increases electron density predominantly at the bent C N- ligands whose N atoms are predicted to be nucleophilic reaction centers.