The synthesis and mesomorphic properties of a series of ferroelectric liquid crystalline polysiloxanes bearing chiral 4-[(4-((n-alkyloxy)sulfinyl)phenyl)ethynyl]phenyl 4-(undecyloxy)benzoate as mesogenic pendant groups are presented. In these polymers, the chirality is introduced via an asymmetric sulfur atom. The synthesis of the materials was possible through three successive polymer-analogous reactions. The last key synthetic step is the polyesterification of the poly((undecyloxy)benzoic acid-methylsiloxane) with the n-alkyl 4-[(4-hydroxyphenyl)ethynyl]benzenesulfinate derivatives, which could be carried out efficiently. Up to 97% overall substitution rates of the siloxane units by the mesogenic moiety could thus be obtained. In this paper are also reported the results of the preliminary investigations of the ferroelectric properties, carried out in the S-C* phase of one polymer. Finally, the comparison of the mesomorphic properties of a sulfinate-based polymer and molecule with their carboxylate-based counterparts is briefly reviewed.