The structures of gas-phase group nine cation-nitrous oxide metal-ligand complexes, M+(N2O)n (M = Co, Rh, Ir; n = 2-7) have been determined by a combination of infrared photodissociation spectroscopy and density functional theory. The infrared spectra were recorded in the region of the N2O asymmetric (N[double bond, length as m-dash]N) stretch using the inert messenger technique and show spectroscopically distinct features for N- and O-bound isomers. The evolution of the spectra with increasing ligand number is qualitatively different for each of the metal ions studied here with only Co+(N2O)n complexes behaving similarly to the coinage metal complexes studied previously. The rich variety of electronic and isomeric structures identified make these species attractive targets for infrared-driven, isomer selective intra-complex chemistry.