The ability to donate or accept charge is a fundamental property of a chemical species. This property is typically rooted in the valence electron count and May be determined from the ionization potential and electron affinity. First-principles theoretical studies have been carried out to show that a cluster may be transformed from a donor to an acceptor by changing only the ligand. Our studies on a chalcogenide Ni9Te6 cluster show that the ionization potential and electron affinity undergo substantial changes as the attachment of phosphine PH3 decreases the ionization potential to be less than that of sodium, whereas the attachment of PCl3 or CO increases the adiabatic electron affinity to be greater than iodine. The ligands change the electronic properties by creating a coulomb well that can shift the electronic spectrum. Studies on Co9Te6(CO)(8) clusters show agreement with experiment and demonstrate that the ideas developed here are applicable to a wider group of clusters.