We synthesized new series of paramagnetic nitroxide radical liquid crystalline (LC) compounds (NR-LCs) with a methylene group as the linking group of one of the side chains and investigated their phase-transition behaviors. NR-LCs with two alkoxy chains show more stable LC phases than those with an alkyl chain instead of one of the alkoxy chains. We reveal by conformational analyses that the planarity of each side-chain moiety influences the stability of LC phases.