Flexible, swellable organosilica tubes are the most remarkable new mesophase generated by co-hydrolysis of tetraalkylammonium-substituted trimethoxysilanes and TEOS. The composites self-organize into lamellar layers or hexagonal tubules, whose elastic walls allow the uptake of anionic or lipophilic species. The hexagonal-tube structure is retained even upon calcination to mesoporous silica (see Figure for a TEM image).