The organization of amino acids in proteins gives rise to local electrostatic environments which play pivotal roles in biological processes like protein folding, drug-target recognition and binding, and enzymatic catalysis. Given the importance of these processes, molecular dynamics (MD) simulations are frequently used to parse and quantify their underlying electrostatic contributions, which may then be used as design principles for novel systems. To ensure these simulations are reliable, computationally-derived parameters need to be benchmarked against experimental results to improve the force �ields (FFs) governing MD. Parameterizations of protein FFs often compare simulations with experimentally-derived secondary and tertiary structures and NMR J coupling constants, among other observables; these comparisons are against either global or local structural properties, but not local electrostatic interactions. Vibrational Stark effect (VSE) spectroscopy interprets changes in the absorption of molecular vibrations through the in�luence of the local environmental electric �ield and therefore provides a direct comparison with the output of simulations. Nitriles (-C≡N) are popular vibrational probes whose VSE facilitates the measurement of the electric �ield projected along the -C≡N bond axis, FC≡N, and, as such, enables the quanti�ication of the strength of noncovalent interactions using an electrostatic scale. Previous work demonstrated that nitrile frequencies of small molecules observed in aprotic solvation environments have a linear correlation with nitrile electric �ields obtained from �ixed-charge (FC) and polarizable (POL) MD simulations (called FC≡N,FC MD and FC≡N,POL MD, respectively). This indicates that nitrile frequencies in aprotic environments can be evaluated within the framework of the VSE, and electric �ieldfrequency calibrations enable the extraction of an electric �ield when a frequency is measured in a new environment, herein termed FC≡N,FC FREQ or FC≡N,POL FREQ depending on the FF used for calibration. Many studies attempted to extract FC≡N,FREQ's for nitriles in protic solvents and more complex H-bonding environments in proteins (where nitriles were introduced via ligands and noncanonical or modi�ied amino acids) for direct comparisons with FC≡N,MD's in these environments. However, the comparisons were complicated by anomalous blueshifts in the nitrile frequencies due to H-bonding interactions which are not captured by the VSE frequency calibrations. In a recent report, we demonstrated that measured nitrile transition dipole moments (TDMs, i.e., the square root of the absorption intensities) vary linearly with electric �ields in both protic and aprotic solvation environments, overcoming the issues observed for frequencies.