A new lamellar mesostructured oxovanadium(V) phosphate, (DDAH)(0.9)(Cl)(0.9)VOPO4. 1.5H(2)O (DDA = dodecylamine), has been synthesized through a (S+X-I0) cooperative mechanism using protonated dodecylamine (DDAH(+)) as structural directing agent. The self-assembling process between 2D-[VOPO4] moieties and (DDAH(+)... Cl-) dipolar ion pairs leads to a second-order staged material in which the surfactant molecules are organized in a interdigitated array occupying the gap between double VOPO4 layers defining the inorganic walls. Besides X-ray powder diffraction and TEM observations, results from IR spectroscopy, thermal analysis, and intercalation reactions suggest that the inorganic framework in the title compound has clear similarities with that observed in VOPO4. 2H(2)O.