Abstract: | Three zinc iodide complexes based on phosphane ligands, namely diiodidobis(triphenylphosphane‐κP)zinc(II), [ZnI2(C18H15P2)2], ( 1 ), diiodidobis[tris(4‐methylphenyl)phosphane‐κP]zinc(II), [ZnI2(C21H21P2)2], ( 2 ), and [bis(diphenylphosphoryl)methane‐κ2O,O′]zinc(II) tetraiodidozinc(II), [Zn(C25H22O2P2)3][ZnI4], ( 3 ), have been synthesized and characterized. Single‐crystal X‐ray diffraction revealed that the structures of ( 1 ) and ( 2 ) are both mononuclear four‐coordinated ZnI2 complexes containing two monodentate phosphane ligands, respectively. Surprisingly, ( 2 ) spontaneously forms an acentric structure, suggesting it might be a potential second‐order NLO material. The crystal structure of complex ( 3 ) is composed of two parts, namely a [Zn(dppmO2)3]2+ cation [dppmO2 is bis(diphenylphosphoryl)methane] and a [ZnI4]2− anion. The UV–Vis absorption spectra, thermal stabilities and photoluminescence spectra of the title complexes have also been studied. Time‐dependent density functional theory (TD–DFT) calculations reveal that the low‐energy UV absorption and the corresponding light emission both result from halide‐ligand charge‐transfer (XLCT) excited states. |