The first examples of lanthanidomesogens that exhibit a low viscous nematic phase are presented. The compounds are one of the rare examples of liquid-crystalline lanthanide complexes that show polymorphism in the mesophase region (smectic A and nematic phases). The temperatures at which the nematic phase occurs are low and the nematic temperature range is broad, which makes these materials interesting for further physical studies. Moreover, the compounds are thermally stable. It is illustrated for the first time that aligned samples of lanthanidomesogens can emitlinearly polarized light.