Although plasmonic nanoparticles are widely utilized in spectroscopy and sensing applications, a quantitative structure-function relationship is lacking. In this proceeding, we discuss measurements of single noble metal nanoparticles using localized surface plasmon resonance (LSPR) spectroscopy, surface-enhanced Raman spectroscopy (SERS), and transmission electron microscopy (TEM) to elucidate structure-function relationships. A recently developed LSPR imaging spectroscopy instrument with an extremely fast camera enables measurement of diffusion constants for individual silver nanoprisms dispersed in water-paving the way for plasmonic particles as dynamic labels in biological systems. Correlated studies involving two or all three of these techniques relate optical properties of the same nanoparticle to its structure. Lastly, single-molecule surface-enhanced Raman spectroscopy of Rhodamine 6G is explored on lithographically fabricated plasmonic structures.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.