In this paper, the effective functionalization of silsesquioxane (HSiMe 2 O) 8 Si 8 O 12 (1) via hydrosilylation of two different functional alkenes is presented. For the first time, such a wide spectrum of statistically bifunctional silsesquioxanes (RSiMe 2 O) ∼4 (R′SiMe 2 O) ∼4 Si 8 O 12 was obtained and characterized. Seventeen new systems with various substituents (Si−H, hydroxyl, ester, epoxy, alkenyl, or alkyl) were prepared by two synthetic approaches. The first method was based on the subsequent hydrosilylation of two alkenes in a one-pot manner, whereas the second one consisted of a twos t e p p r o t o c o l i n w h i c h i n t e r m e d i a t e s ( R S i -Me 2 O) ∼4 (HSiMe 2 O) ∼4 Si 8 O 12 were isolated and then reacted with the second alkene, in the presence of the same or a different catalyst. Resulting systems due to the presence of two various groups attached to the silsesquioxane cage can be considered as potential cores for the synthesis of (hyper)branched molecules or macromolecules.