An electrochemical technique was used to investigate pK(a) values of some substituted secondary alicyclic (SA) amines, pyridines (py), anilines (AN), and triethylamine (Et3N) in different ionic liquids. The method involves cyclic voltammetry at a platinized Pt electrode. The experimental data were correlated with pK(a) values reported previously in aqueous solution, and Hammett parameters were correlated with pK(a) values in ionic liquids to determine rho values in these media.