The synthesis and comparative study of mesomorphic properties of aromatic polyesters containing the nonlinear T-shaped mesogenic sequences based on 1,4-dihydroxy-2-benzoylbenzene and hinge heteroatoms—oxygen (polyester I) or sulfur (polyester II)—have been performed. Polyester II lacks liquid-crystalline properties, in contrast to the oxygen-containing analog I demonstrating the mesomorphic behavior. In the case of polyester II samples, there is a large scatter in dynamooptical characteristics estimated in dilute N-methylpyrrolidone solutions. This behavior of polyester II is apparently associated with restriction of intramolecular mobility because of interaction between valence shells of sulfur atoms giving rise to bridge S···S bonds.