Polysiloxane‐analogous Si–S compounds have so far not been reported. Transsilylation reactions of the solid pyridine adduct of HSiCl3 with gaseous Me3Si–S–SiMe3 yielded perhydridopolysilathianes. 29Si NMR, FTIR, and Raman spectroscopy; elemental and thermal analysis; XRD; SEM; and gas‐adsorption measurements indicated that the product consists of D‐, T‐, and Q‐units with a composition of ([H2SiS]1.2[HSiS1.5]2.6[SiS2]1.0)n. Formation of the latter is caused by pyridine‐catalyzed dismutation reactions. The polymer is mesoporous with a surface area of 187 m2 g–1; furthermore, it is amorphous and insoluble in organic solvents.