The prediction using COSMO-RS which majorly rely on hydrogen bonding mechanism, showed inconsistent results against experimental data. The present study using Raman spectroscopy has led to the same conclusion where π-electron density becomes a vital viewpoint in the process of screening potential ILs for desulfurization. The use of a new complementary method which estimates the aromaticity index (AI) for cation and double bond equivalent (DBE) for anion selection showed good agreement between the literature and experimental results. The AI and DBE methods were later used to select the appropriate combination of cation and anion of ILs for extractive desulfurization study
