A series of N-alkyl-N-methylpyrrolidinium (RMPyr + , where R=E: ethyl, B: butyl, and H: hexyl) and N-butylpyridinium (BPy + ) salts based on the fluorocomplex anions, BF 4 − , PF 6 − , SbF 6 − , NbF 6 − , TaF 6 − , and WF 7 − , have been synthesized and their thermal behavior has been investigated. The melting points of the RMPyr + salts are above room temperature with the trend; BMPyrAF 6 <HMPyrAF 6 <EMPyrAF 6 for the hexafluorocomplex salts. Some of the salts containing BMPyr + and HMPyr + exhibit phase transitions in the solid states. Similar melting points of BPy + salts of PF 6 − , SbF 6 − , NbF 6 − , TaF 6 − , and WF 7 − are observed at around 350K. Ionic conductivity and viscosity for BMPyrNbF 6 (3.0mScm −1 and 164cP at 328K) are similar to those for BMPyrTaF 6 (3.0mScm −1 and 165cP at 328K), resulting from the similarity of the anions in size. The activation energies of ionic conductivity for the NbF 6 − and TaF 6 − salts are 18 and 20kJmol −1 , and those for viscosity are 23 and 25kJmol −1 , respectively calculated by Arrhenius equation in the temperature range between 328 and 348K. Electrochemical windows of BMPyrNbF 6 , BMPyrTaF 6 , and BMPyrWF 7 are about 4.0, 5.0 and 3.1V, respectively.