We will compare different approaches to generating effective antibonding orbitals: in particular we are interested in whether the second order antibonding (AB2) MOs significantly improve upon the Sano antibonding orbitals, as measured by usage-relevant metrics obtained from a set of numerical experiments. We will first examine orbital plots, orbital energies, and orbital variances. We then test the applicability of Sano and AB2 MOs to several valence correlation methods: coupled cluster valence bond (CCVB), complete active space configuration interaction (CASCI), and complete active space self-consistent field (CASSCF). Next, we look into their uses for describing valence excited states. For basis set, we are using the Dunning basis set family and Ahlrichs. These are available in Q-Chem 5.3 with an automated detection of bonding orbitals.