Ionic liquid crystalline compounds with a long terminal chain and their nonionic family were synthesized. The ionic liquid crystalline compound (I-7) with a heptyloxy terminal chain exhibited smectic A and C phases. On the other hand, a nonionic family of ionic I-7 showed a smectic A phase. In the case of the ionic liquid crystalline compound (I-4) with a butyloxy terminal chain, a smectic A phase was formed. A nonionic family of ionic I-4 did not show a liquid crystalline phase. The isotropization temperatures of the ionic liquid crystalline compounds were higher when compared to the nonionic family. These results exhibit that the ionic interactions act effectively in forming a liquid crystalline phase with enhanced thermal stability and enable the formation of the fluid smectic phases. In ionic I-7, the formation of the smectic C phase that the nonionic family of I-7 did not exhibit was led through the balance between an anisotropy formed by the mesogenic groups and the ionic interactions.