The unexpectedly aqueous stable bis-tellurium cationic complex [Co(dmgH)2{PhTe(CH2)3SO3Na}2]+(1+) (dmgH− = dimethylglyoximate) has been fully characterized in the solid state and in solution. The UV–Vis spectrum of 1+ differs from that of earlier cobaloximes, exhibiting a new low energy band centered at λmax = 425 nm (ε ∼ 26155 dm3 mol−1 cm−1) and assigned with DFT calculations to allowed LMCT transitions. 1H, 13C, and 125Te NMR spectra show unequivocally that two diastereomers exist equally in water, 50% of the achiral C2h meso-[Co(dmgH)2{R,S-PhTe(CH2)3SO3Na}2]+ and 50% of the chiral C2rac-[Co(dmgH)2{PhTe(CH2)3SO3Na}2]+ (25% of each enantiomer [Co(dmgH)2{R,R-PhTe(CH2)3SO3Na}2]+ and [Co(dmgH)2{S,S-PhTe(CH2)3SO3Na}2]+). The solid-state structure of the meso diastereomer has been solved. Neutral mono-tellurium complexes [CoCl(dmgH)2{Te(p-MeO–C6H4)2}](2) and [CoCl(dpgH)2{Te(p-MeO–C6H4)2}](3) (dpgH− = diphenylglyoximate) have also been characterized in the solid (3) state and in solution (2 and 3). The structural results provide the first examples of Co(III)–Te bonds. The solid-state structure of the related cobaloxime salt [Co(dmgH)2(py)2][CoCl2(dmgH)2] obtained during one synthesis is also reported.