Microcrystalline bismuth methoxide, BiOOCH3, was synthesized by reacting bismuth nitrate pentahydrate in a sodium hydroxide/methanol mixture. The structure was determined with a Rietveld refinement in space group P4/nmm (a = 3.740 Angstrom, c = 10.513 Angstrom) from X-ray powder data. The thermochemical reactivity is discussed with respect to its dependence of the gas atmosphere and the morphology as well as with respect to the formation of bismuth oxide exhibiting tailor-made textures and morphologies. The significance of the title compound as potential precursor compound for the generation of ternary or polynary oxides is discussed.