In this paper we investigate the photodissociation, geminate recombination and relaxation dynamics in size-selected I-2(-).(CO2)(n) cluster ions using an electronically nonadiabatic molecular dynamics method and a model Hamiltonian gained from diatomics-in-ionic systems (DIIS). These theoretical studies make contact with recent time resolved pump-probe and photoelectron detachment experiments. Our studies reveal a rich excited state dynamics in which various competing electronic relaxation channels as well as vibrational relaxation influence the recovery of signal in these experiments.