A series of the rod-like and Y-shaped liquid-crystalline (LC) compounds with per- and semifluorinated tails was synthesized with variation of the tail length. The perfluoroalkyl tails enhanced stability of the mesophase both for rod-shaped and Y-shaped LC compounds. The effect of semifluoroalkyl tails is different. For rod-shaped compounds such substituents strongly suppress LC properties. For Y-shaped compounds, smectic properties are stabilized.