Quantum chemical calculations based on density functional theory have been performed on Cr(CO)6, (eegr6-C6H6)Cr(CO)3 and (eegr6-C6H6)Cr(CO)2(CS) at the local and nonlocal level of theory using different functionals. Good agreement is obtained with experiment for both optimized geometries and metal-ligand binding energies. In particular, a comparison of metal-arene bond energies calculated for the (eegr6-C6H6)Cr(CO)3 and (eegr6-C6H6)Cr(CO)2(CS) complexes correlates well with kinetic data demonstrating that substitution of one CO group by CS leads to an important labilizing effect of this bond, which may be primarily attributed to a larger pgr-backbonding charge transfer to the CS ligand as compared with CO.