Experimental data on extractive desulfurization (EDS) of dibenzothiophene (DBT), thiophene, benzothiophene, and other substituted derivatives of sulfur from liquid fuel using trihexyl(tetradecyl)phosphonium hexafluorophosphate ([THTDP][PF6]) have been presented. The Fourier transform infrared spectrophotometer, H-1-NMR, C-13-NMR, and P-31-NMR analysis have been discussed for molecular confirmation, and conductivity, solubility, and viscosity analyses of ([THTDP][PF6]) were investigated. The effects of time, temperature, S-compounds, ultrasonication, and recycling of ([THTDP][PF6]) on DBT removal from fuel were examined. Also, desulfurization of real fuels and multistage extraction was also tested. The data and results provided the significant insights of phosphonium ionic liquids as a promising solvent for EDS.