a Four novel Zinc-NHC alkyl/alkoxide/chloride complexes (4, 5, 9 and 9′) were readily prepared and fully characterized, including X-ray diffraction crystallography for 5 and 9′. The reaction of N-methyl-N′-butyl imidazolium chloride (3.HCl) with ZnEt 2 (2 equiv.) afforded the corresponding [(C NHC )ZnCl(Et)] complex (4) via a protonolysis reaction, as deduced from NMR data. The alcoholysis of 4 with BnOH led to quantitative formation of the dinuclear Zn(II) alkoxide species [(C NHC )ZnCl(OBn)] 2 (5), as confirmed by X-ray diffraction analysis. The NMR data are in agreement with species 5 retaining its dimeric structure in solution at room temperature. The protonolysis reaction of N-(2,6-diisopropylphenyl)-N′-ethyl methyl ether imidazolium chloride (8.HCl) with ZnEt 2 (2 equiv.) yielded the [(C NHC )ZnCl(Et)] species 9. The latter was found to be reactive with CH 2 Cl 2 in solution and to cleanly convert to the corresponding Zn(II) dichloride [(C NHC )ZnCl 2 ] 2 (9′), whose molecular structure was also elucidated using X-ray diffractometry. Unlike Zn(II)-NHC alkoxide species 1 and 2, which contain a NHC flanked with an additional N-functional group (i.e. thioether and ether, respectively), the Zn(II) alkoxide species 5 incorporates a monodentate NHC ligand. The Zn(II) complexes 1, 2 and 5 were tested in the ring-opening polymerization (ROP) of trimethylene carbonate (TMC). All three species are effective initiators for the controlled ROP of trimethylene carbonate, resulting in the production of narrow disperse PTMC material. Initiator 1 (incorporating a thioether moiety) was found to perform best in the ROP of TMC. Notably, the latter also readily undergoes the sequential ROP of TMC and rac-LA in the presence of a chain-transfer agent, leading to well-defined and high-molecular-weight PTMC/PLA block copolymers.