Ordered mesoporous NaTaO₃ thin films with both 3D honeycomb and nanopillar-like structures were successfully produced through sol–gel templating using a novel amphiphilic diblock copolymer, PIB₅₃-b-PEO₄₅, as the structure-directing agent. These nanocrystalline materials not only exhibit enhanced UV-light photocatalytic activity but are also able to maintain stable performance.