A chemical compound which has an electron donor group, an electron acceptor group, and a conjugated bridging element bridging between the electron donor group and the electron acceptor group. The chemical compound has a readily displaceable electron, is capable of emitting photoluminescent radiation. A dipole character is present therein only in the excited state of the compound. The compounds are suitable for use in optical devices and, particularly, can be used for photoluminescence quenching devices.