This study investigates how blue (similar to 460 nm) photoluminescence (PL) from mesoporous silica (MS) films depends on the nanostructure and chemistry of the pores. Reducing pore-size and pore-wall can increase the total area of the pore-surfaces, and therefore the number of radiative recombination centers, within the MS matrix, enhancing PL efficiency. Moreover, the number of silianol groups on pore-surfaces, which absorb moisture and degrade the PL of the MS films, is greatly reduced by silylating MS with hydrophobicity, yielding long-term stable luminescence. The quantum-efficiency of PL and the electroluminescence of the MS films are measured about 5.0 x 10(-4) and 1.0 x 10(-6), respectively. (C) 2004 The Electrochemical Society.