Polymolybdate/1, 10-decanediamine self-assembled films were fabricated by self-assembly of 1, 10-decanediamine and Na2MoO4 solutions with different pH values. It is found that the photochromic responses of the films increase with decreased pH value of the Na2MoO4 solution. It is identified that the pH value can affect greatly the species of polyanion inorganic building blocks in the Na2MoO4 solution, thus resulting in the polymolybdate/1, 10-decanediamine self-assembled films with different structure and photochromic properties. (c) 2005 Elsevier B.V. All rights reserved.