C and Si nanostructures have received considerable attention since their great potential applications in novel light emitting devices, bio-imaging, solar and optical devices and novel catalysts design.Notably, for the unique characteristics of photoluminescence (PL), we can expect that the research in the strong and tunable PL of C quantum dots (CQDs) and Si quantum dots (SiQDs) will further enhance their versatile properties, which is extremely important both fundamentally and technologically.In this talk, I will summarize our recent research on C and Si nanostructures in synthesis and their applications in energy transfer and catalysis.