Recent Advances in Luminescent Monomeric, Multinuclear, and Polymeric Zn(ii) and Cd(ii) Coordination Complexes

‘Luminescence research has a long history full of splendor and surprise, and a bright future, promising variegated applications to probe molecules and crystals, to visualize atomic phenomena, …’ H. J. Queisser, 1981 This article briefly summarizes recent progress on the luminescence studies of monomeric, multinuclear, and polymeric Zn(ii)/Cd(ii) coordination complexes, involving spectroscopic, photophysical, and photochemical studies, as well as molecular and electronic structural investigations, focussing mainly on the interplaying factors that govern the luminescent origin of the lowest-lying emissive states. Current results show that, for Zn(ii)/Cd(ii) coordination complexes in general, the nature of the metal centres and ligands and the rigid metal-oxy (or -hydroxy) clusters are factors governing their luminescent origin of the lowest-lying emissive states; different types of ligands and coordination structures may result in different emission mechanisms.