Fabricating dense polycrystalline MOF films with optical quality involves time-consuming, inefficient processing in a highly controlled environment. For example, high-quality, optically transparent HKUST-1 (Hong Kong University of Science and Technology 1) thin films can currently be grown only in an inert, humidity-controlled atmosphere. Some of us demonstrated recently that MIL-68(In) (Matériaux de l'Institut Lavoisier) thin films can indeed be made within minutes, but MIL-68(In) currently remains a unique example in those terms.