Phenothiazine-triphenyltriazine (PTZ-TRZ, inset in Figure ), composed of an electron-donor PTZ and an electron-acceptor TRZ, has unique optical properties originating from the CT excited states. PTZ-TRZ shows dual emission (Figure ) upon photoexcitation and the photophysical properties of both the emission bands depend on the permittivity of a solvent, implying that the two bands originate from two different CT excited states . Quantum chemical calculations predicted that PTZ-TRZ has two stable geometries, quasi-axial conformer (q-ax.) and quasi-equatorial conformer (q-eq.) (Figure ), in both the ground and excited states . The two emission bands are expected to be assigned to the emissions from these two conformers. Most of dual emission in an organic molecule were attributed to the transitions from a CT excited and a locally excited (LE) states ; therefore, this dual emission from two CT excited states of two conformers is quite unusual.