Abstract: Metal and semiconductor quantum dots (QDs) exhibit unique size and composition dependent optical properties. The key elements that determine their optical properties are localized surface plasmon resonance in metal nanoparticles and excitons in quantum dots. The presentation includes two topics. One, single particle spectroscopy in conjugation with transmission electron microscopy is used to monitor the LSPR of bimetallic nanoparticles during reactions at the single particle level. The LSPR is closely related the morphology of the nanoparticles, therefore, provides insight into the reaction mechanisms. Two, we study plasmon-exciton interaction of single QDs near metal nanoparticles. When QDs are placed near Au nanoparticles, their exciton/multiexciton emission lifetimes and quantum yields are modified. At the single QD level, we found that biexciton emission of the QDs near Au nanoparticles was enhanced, and the extent of enhancement dependent on the excitation wavelength. The emission of single QDs changes from photon antibunching to bunching by exciting the QDs close to the plasmon resonance. These studies suggest that plasmonic structures can be used to modify the exciton/multiexciton emission efficiency of QDs.