A series of liquid-crystalline polyesters has been synthesized in which the mesogenic perfluoroalkylsulfonyl sidechain is directly linked to the hydrocarbon polyester backbone without a spacer. The liquid-crystalline phase appears to be smectic B or A from X-ray data. Interesting differences in the mesophase transition temperatures and enthalpies are observed along the series, as the hydrocarbon backbone is changed. Differences are also seen in layer spacing from X-ray data, which increases as the hydrocarbon content increases. We discuss these in relation to the length of the backbone segments.