Octaphenylsilsesquioxane (OPS) derivatives represent a class of high functionality building blocks with perfect three-dimensional symmetry for the construction of rigid and highly porous polymers. Copper-mediated in-situ homocoupling of an OPS derivative with eight para-disposed triple bonds yields a porous network with surface areas tip to 1000 m(2)/g. Introducing a monoalkyne capping agent to lower cross-linking density led to a similar to 200 m(2)/g increase in surface area. Exceptional thermal robustness of the silsesquioxane cage and strong covalent bonds resulting from the cross-linking process render the resulting porous networks stable to heat and water.