Large pore (a = 150-200 A) wormlike and highly oriented cubic (IM3m space group) and 2D-hexagonal (P6m) mesostructured xerogels have been reproducibly synthesised by Evaporation-Induced Self Assembly (EISA). Mesostructure control was attained by changing the template (nonionic block copolymer) and water (h = [H2O]/[Si]) ratio.