We focus on interesting physical/chemical phenomena of molecules and materials which can be applied to energy storage, catalysis, molecular machines, and nanomaterials. Based on physical/chemical knowledge, theory development, and computational analysis, we try to understand the fundamental principles of chemical reactions, molecular interactions, light-matter interactions, energy transfers, electron transfers, exciton transfers, and so on. We perform quantum chemical calculations, (excited-state) molecular dynamics simulations, machine learning, and quantum computing to investigate unknown interesting physical/chemical behaviors.