We control the physical properties of matter by unveiling its transient structures and even creating ones of exotic functionality based on the deep understanding of light-matter interactions and structure-function relations. To this end, we use frontier imaging tools, an advanced ultrafast electron microscope capable of filming atomic motions and an ultrafast optical microscope for tracking electronic-state dynamics. The areas of research include the study of elementary electronic and structural dynamics in 2D matter and nanomaterials, particularly nonequilibrium photoinduced phase transformations, ultrafast electron-phonon interactions, ultrafast chemical/biological dynamics, and exciton-carrier dynamics in photovoltaics and light-emitting devices.