A new fluorescence-quenched ternary complex, Cu2+/DMABN/beta -CD, has been synthesized using beta -cyclodextrin (beta -CD), copper ions (Cu2+), and 4-(dimethylamino) benzonitrile (DMABN). The significant quenching of DMABN fluorescence is realized through a photoinduced electron-transfer process between DMABN and Cu2+. On the basis of the photochemical properties of the ternary complex, we have proposed a Cu2+/DMABN/beta -CD complex structure with a 2:2:2 molar ratio. To further investigate the ternary complex and explore its potential applications in bioanalysis, we have adopted a novel strategy to restore the quenched fluorescence of DMABN when the complex interacts with an important neurotransmitter, glutamate. The restoration of DMABN fluorescence in the ternary complex is complete and fast upon glutamate interaction. The new complex synthesis and the restoration of the quenched fluorescence processes enable a better understanding of cyclodextrin-based chemistry and also the exploration of novel bioanalysis techniques for neurotransmitters and amino acids. GABA and NMDA have also been used to interact with the ternary complex to restore its fluorescence. Different binding capabilities with the complex show that there are significant differences in binding affinity with different ligand molecules. The new complex and the restoration process will be further explored for bioassays for amino acids and neurotransmitters.