Densities and thermal conductivities are reported for a series of N-alkylpyridinium tetrafluoroborate compounds with butyl (N-butylpyridinium tetrafluoroborate), hexyl (N-hexylpyridinium tetrafluoroborate) and octyl (N-octylpyridinium tetrafluoroborate) groups. The densities were measured with a vibrating tube densimeter over the temperature range 293-353 K at pressures <= 20.0 MPa. The transient short hot wire method was used to measure thermal conductivity over the temperature range 294-335 K at pressures <= 20 MPa. It was found that the effect of alkyl chain length on thermal conductivities in N-alkylpyridinium tetrafluoroborates is the same degree as 1-alkyl-3-methylimidazolium tetrafluoroborates. The experimental values at 293 K and 0.1 MPa were consistent with the predicted values proposed by Froba et al. (C) 2012 Elsevier B.V. All rights reserved.