In this computational study, the 1 JC-H coupling constants of a large series of azolium cations were calculated to evaluate whether this easily accessible experimental property can be used to gauge the σ-donation ability of the corresponding carbene ligand. The calculated 1 JC-H coupling constants were compared with other experimental data as well as other calculated electronic parameters related to σ-donation of the carbenes. The main conclusion is that 1 JC-H of azolium compound is a more reliable experimental probe, compared to HEP or 1 H or C NMR shifts, to measure the σdonation capability of the corresponding carbene. However, the comparison with the calculated σ-donation contribution from the ETS-NOCV method highlights certain issues with 1 JC-H, especially when dealing with very different compounds. Its effectiveness as a descriptor is reasonable for most mono-and diaminocarbenes but diminishes when comparing them with acyclic (aryl)amino carbenes or C-ligands with different backbones. In the same vein, while both HEP and 1 JC-H correlate well within specific carbene classes regarding the effects of substituents, caution is needed when extending this correlation across different carbene classes. Another significant conclusion is that the energy of the carbene's lone pair, often used to describe σdonation ability, turns out to be a poor indicator of this property. Conversely, ELP is useful for assessing the carbene's basicity, which is not provided by 1 JC-H. Finally, these findings confirm that the hybridization of the carbon in the C-H bond of the azolium, rather than that of the carbene's lone pair, approximately correlates with 1 JC-H.