We report the synthesis of highly crystalline and thermally stable mesoporous titanium oxide and niobium oxide with uniform and controllable pores by employing laboratory-made polystyrene-b-poly(ethylene oxide)s (PS-b-PEOs) as structure-directing agents for combined assembly of soft and hard chemistries (CASH). The structure-directing agent PS-b-PEO has been simply synthesized via atom transfer radical polymerization (ATRP) method. With the increase of molecular weight of PS-b-PEO, the pore size of TiO(2) has been tuned in the range of 14.9-20.7 nm. The highly crystalline CASH-PS-TiO(2) exhibited promising photocatalytic activity in both hydrogen evolution and methylene blue (MB) degradation compared to conventional TiO(2) templated by Pluronic P123. Notably, the approach used in this research combines the advantages of CASH and ATRP and can hence be easily adopted by researchers without any prior experience in polymer synthesis. (C) 2011 Elsevier Inc. All rights reserved.