In this work, molecular-symmetry enhanced (CO)-C-13 natural abundant isotopic infrared transition was identified in Mn(CO)(5)Br dissolved in CCl4 by FTIR spectroscopy. Diagonal and associated off-diagonal two-dimensional IR (2D IR) peaks of the (CO)-C-13-species were found to be spectrally separated from the all-(CO)-C-12 species, allowing a direct probe of the C-13 natural abundant ensemble. Temperature-dependent FTIR experiment showed no evidence of ligand exchange in the metal carbonyl complex. Intramolecular vibrational redistribution dynamics among the CO stretching vibrational states were extracted using population-time dependent 2D IR diagonal and off-diagonal peaks for both radial mono-(CO)-C-13 and all-(CO)-C-12 isotopomers. This work demonstrates the potential use of natural abundant isotopic molecular species as a probe for revealing equilibrium and nonequilibrium structural dynamics in condensed-phase molecular systems.