The photochemical deposition of indium oxide films from thin films of indium (III) 2-ethylhexanoate is described. The photolysis of thin films of indium (III) 2-ethylhexanoate results in the fragmentation of the carboxylate ligand and the production of indium along with volatile organic products. When conducted in air, the product of the reaction is indium oxide. Films react depending upon the thickness such that thinner films react more efficiently. This results in a variation in the quantum yield for reaction from near 0.23 for thin films to less than 0.0034 for thicker films. This effect is interpreted as due to partial order within the amorphous precursor film resulting in a lower photosensitivity. Films constructed of indium (III) 2-ethylhexanoate were used to deposit lines of less than 2 micron feature size lithographically using a contact mask.