Mutual solubilities of pyridinium-based tetrafluoroborates (namely, 1-butylpyridinium tetrafluoroborate, 1-butyl-2-methylpyridinium tetrafluoroborate, 1-butyl-4-methylpyridinium tetrafluoroborate, and 1-hexyl-pyridinium tetrafluoroborate) and toluene were obtained at (298.15, 318.15, and 338.15) K. The data were acquired by means of an experimental procedure utilizing gas chromatography and a gravimetric method. The results show that the liquid liquid equilibrium in the studied systems is strongly asymmetrical. While the mole fraction solubility of the pyridinium-based ionic liquids in toluene ranges from 1.0.10(-5) to 5.2.10(-5), the solubility of toluene in these ionic liquids varies from 0.318 to 0.579 in mole fraction. The experimental data were correlated with a semiempirical equation. Parameters of the nonrandom two-liquid (NRTL) equation were evaluated as well.