N-butyl-(N-hydroxyethyl) ammonium based protic ionic liquids (PILs) were synthesized.

Density, speed of sound, electrical conductivity and viscosity were measured for studied PILs.

Transport property data were fitted to Vogel–Tammann–Fulcher (VTF) equation.

FT-IR spectrum was helpful to explain the hydrogen bonding between ions.

Measured and derived properties were analyzed in terms of chemical structure of PILs.