Current work on inorganic electrochromic materials and devices is reviewed briefly, and the emphasis on thin films of W oxide and Ni oxide is pointed out. New results are presented on the optical properties for sputter-deposited thin films of these two materials: for Li+ intercalated substoichiometric W oxide, it is shown that the absorption can be reconciled with an extended "site saturation" model accounting for electronic transitions between W ions in 6+, 5+, and 4+ states, and for H+ deintercalated Ni oxide, it is found that the coloration efficiency is higher than in prior work presumably as a consequence of the nanocrystalline structure ensuing from the deposition conditions. (c) 2005 Elsevier B.V. All rights reserved.