Both localized and lattice plasmon resonances offer unique opportunities to modify the emission behavior of molecular systems. In the weak-coupling regime, both linear and non-linear optical phenomena can be enhanced by the presence of a plasmonic surface, improving the performance of sensing platform, biological tags or photonic architecture. In the strong-coupling regime the interaction can directly modify the energy landscape of the system, creating exciting opportunities for the discovery of new catalysts or optoelectronics devices.