A so-called constrained optimized effective potential (COEP) method for excited states (ESs) is briefly reviewed. In contrast to known density functional theory and OEP-based approaches for ESs, the COEP method explicitly introduces orthogonality of the Kohn–Sham (KS) ES function to the lower states of the same symmetry. This makes it possible to solve the KS-like equation so that, “variational collapsing” is avoided and any appropriate local potential can be handled. In particular, we implemented a local effective expressed as a direct mapping of the external potential, that is, = . It is shown that excited and core-ionized states can be treated within the framework of a unified computational approach. Our practical calculations demonstrate that the exchange-only implementation of the COEP method in conjunction with expressed in terms of the external potential is capable of delivering reasonable results on the energies of singly excited as well as core-ionized states and can be easily applied to both atoms and molecules. © 2012 Wiley Periodicals, Inc.