Local intramolecular mobility in regular linear polyesters with flexible siloxane and more rigid ester aromatic fragments providing in some cases LC state was studied by dielectric spectroscopy. The dielectric transitions related to the local mobility in the ester aromatic fragment were observed. It was shown that two local relaxation processes (beta＇ and beta ") with different mechanisms of mobility took place in these systems. One of them, the beta " process. having the shortest relaxation times (tau similar to 10(-7) s) is connected with the motion of ester groups and phenyl rings. It is determined only by intramolecular interactions. The second local process, beta＇, reflects the motion of the polar ester group including the central part of the ester aromatic fragment (tau similar to 10(-1)-10(-4) s). This motion can be realized at the beginning of flipping of the aromatic ring. Parameters of the beta＇ process depend on intra- and intermolecular interactions.