The new pincer ligand 2,6-bis[(1,3-di-tert-butylimidazolin-2-imino)methyl]pyridine (TL^tBu) has been prepared in high yield from 2,6-bis(hydroxymethyl)pyridine (1) and 1,3-di-tert-butylimidazolin-2-imine (3). Reaction of TL^tBu with [Cu(MeCN)₄]PF₆ affords the highly reactive copper(I) complex [(TL^tBu)Cu]PF₆, [5]PF₆, which forms the stable copper(I) isocyanide complexes [6a]PF₆ (ν_CN = 2179 cm⁻¹) and [6b]PF₆ (ν_CN = 2140 cm⁻¹) upon addition of tert-butyl or 2,6-dimethylphenyl isocyanide, respectively. For the cations 6a and 6b, DFT calculations reveal ground-state electronic structures of the type [(TL^tBu-κN¹:κN²)Cu(CNR)] with tricoordinate geometries around the copper atoms. Exposure of [5]PF₆ to the air readily leads to trapping of atmospheric CO₂ to form the square-planar complex [(TL^tBu)Cu(HCO₃-κO)]PF₆, [7]PF₆, with the bicarbonate ligand adopting a rarely observed monodentate coordination mode. In chlorinated solvents such as dichloromethane or chloroform, [5]PF₆ rapidly abstracts chloride by reductive dechlorination of the solvent to yield [(TL^tBu)CuCl]PF₆, [8]PF₆ quantitatively. Reaction of TL^tBu with copper(I) bromide or chloride affords complexes 9a and 9b, respectively, for which X-ray diffraction analysis, low-temperature NMR experiments and DFT calculations reveal the presence of a κ²-coordinated ligand of the type [(TL^tBu–κN¹:κN²)CuX]. In solution, complex 9b undergoes slow disproportionation forming the mixed-valence copper(II)/copper(I) system [(TL^tBu)CuCl][CuCl₂], [8]CuCl₂ with a linear dichlorocuprate(I) counterion.