Using density functional theory at D3-B3LYP/aug-cc-pVDZ level combined with the conductor-like polarizable continuum model (CPCM) solvent model, a study of the IR spectrum of ${\mathrm{H}}_{\mathrm{2}}\mathrm{O}$:HCN mixtures is reported. The CPCM solvent effect notably enhances the accuracy of the IR spectra compared to gas-phase calculations, while the dielectric constant value has minimum impact on the final spectrum. An optimized methodology is suggested that effectively minimizes the root mean square deviation between theoretical and experimental data. This novel approach not only enhances the quality of the final IR spectra but also captures relevant spectral features, highlighting its potential to decipher molecular interactions in such intricate mixtures.