H/D isotope effects on nuclear shielding (IENS) have found applications in the study of reaction kinetics, chemical and conformational equilibria, and non-bonded interactions. In particular, they are especially well-suited to investigate hydrogen bonded (H-bonded) systems. In this presentation, we demonstrate that H/D IENS are indeed a powerful tool to scrutinize interionic H‑bonds in ionic liquids (ILs), using 1-n-alkyl-3-methylimidazolium salts as examples. Results obtained with protonated and deuterated isotopologues of 1‑n‑butyl‑3-methylimidazolium chloride ([C₄mim]Cl), tetrafluroborate ([C₄mim]BF₄), and hexafluorofosphate ([C₄mim]PF₆) indicate that IENS on the ^35/37Cl and ¹⁹F resonances of the anions, or D^35/37Cl(H,D) and D¹⁹F(H,D), allow to identify and differentiate H-bonds between the anion and the different aromatic protons on the cation. Furthermore, IENS measured on sequentially deuterated [C₄mim]BF₄ and [C₄mim]PF₆ isotopologues reveal the formation of aliphatic C‑H⋅⋅⋅X hydrogen bonds between the fluorinated anions and hydrogens along the N-alkyl sidechains of the cations. Our findings also indicate that the interactions between the fluorinated anions and hydrogens on the C‑1’ and C-1” position of the N-alkyl sidechains are comparable to, and in some cases stronger than, those involving protons on the aromatic ring, underscoring the role that these weak interionic forces have on the local ordering of imidazolium salts in the liquid state. The methodology also shows that the length of the N-alkyl sidechain anchored on the N-1 position has no sizable effect on the strength of interionic H-bonds in this type of ILs. Current studies involving variations on the sidechain structure, was well as applications of the approach to the study of other systems bearing NMR-active nuclei, are discussed.