Microwave-assisted synthesis of novel imidazolium-based ionic liquid crystalline dimers

Microwave promoted synthesis of novel imidazolium-based ionic liquid crystalline dimers containing calamitic–calamitic, calamitic–discotic and discotic–discotic moieties is reported. Classical reactions failed to produce these dimers. The thermotropic liquid crystalline properties of these salts were investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray diffractometry. These salts, except the one having calamitic–discotic units, with bromide as counter ion were found to be mesomorphic over a wide temperature range.