Designing materials as we desire is one of the most fascinating research area, and some of the most useful areas for developing new materials are their medical- and energy-related applications. In order to design materials such that they have functions and properties as we desire, it is critical to understand how the smallest unit that composes materials – molecules – changes the properties of material by their composition and structure. I would like to focus on developing organic/inorganic nanomaterials for (1) medical-related applications to understand, control, and modify the mechanism inside the cells, and (2) energyrelated applications such as catalysts for organic reactions, electric/magnetic switches, and sensors for chemicals. Furthermore, based on the current knowledge, it is extremely important that we seek for next steps to design more efficient and functional materials either by combining various existing properties or by discovering novel properties.