Stable silica-based zeolites with increased porosity are in demand to allow adsorption and processing of large molecules, but challenge our synthetic ability. Here we report a novel, highly stable pure silica zeolite, ZEO-3, with a multidimensional, interconnected system of extra-large pores open through windows made by 16 and 14 SiO4 tetrahedra, which is the less dense polymorph of silica known so far. This zeolite is formed by an unprecedented 1D-to-3D topotactic condensation approach from a chain silicate. With a specific surface area over 1000 m2/g, ZEO-3 shows an extraordinary performance for Volatile Organic Compounds abatement and recovery and potential as a catalyst for the conversion of bulky molecules after incorporating heteroatoms as active centers.