A variety of side chain liquid crystalline ionic polysiloxanes with quaternized ammonium groups incorporated into the mesogenic moiety or into the spacer have been synthesized and studied by a combination of DSC, TGA, polarizing microscopy and X-ray diffraction. The polysiloxanes exhibit a nematic mesophase. Due to their flexible main chain, the transition temperatures are low. Thermal stability and liquid crystallinity of quaternized and unquaternized polysiloxanes are compared. It appears that in these ionic polymers the geometry of the mesogenic group plays an important part in the development of the mesophase.