Organically-modified porous silicates have been prepared according to a one-pot synthetic approach. A mixture of phenyltriethoxysilane and tetraethoxysilane was reacted with an acidic solution of cetyltrimethylammonium bromide (CTAB). Depending on the preparation conditions, not only the hexagonal (2d, p6m) but also a cubic phase has been prepared analogous to the already reported SBA-1 phase, whose X-ray pattern matches the (Pm3n) space group. To our knowledge, it is the first time that this phase is obtained with CTAB as structuring agent, which suggests specific interactions between the phenyl groups and the surfactant polar head group. The surfactant was removed by solvent extraction or calcination at 350°C, without any alteration of the ordering: a cubic porous silicate network functionnalized by phenyl groups was thus obtained. Calcination could even be performed at 600°C to prepare a pure silicate network that still exhibits the same cubic symmetry.