Chlorine-containing poly(siloxane/double-decker silsesquioxane) (PeCl) was prepared in high yield at ambient room temperature via dehydrocarbonative polycondensation reaction between di[(3-chloropropyl) isopropoxysilyl]-bridged double-decker octaphenylsilsesquioxane (DDSQ) and hexame-thyltrisiloxane. Particular attention for this polymer was also given to its functionalization through substitution reaction, especially due to nucleophilic substitution on the side-chain of polymer at silsesquioxane units. But more important, the use of halogen exchange method with bromine anion allows the formation of more reactive, bromine-containing poly(siloxane/double-decker silsesquioxane) (P-Br), which enables further post-substitution modification reactions in a POSS unit. The glass transition temperatures (T-g similar to 15 degrees C) of both halogenated polymers were significantly higher than poly(dimethylsiloxane) (PDMS). High transparency of polymers with hydrophobic surface could be found from solvent-casting thin film. (C) 2016 Elsevier Ltd. All rights reserved.