Förster fluorescence resonance energy transfer (FRET) is one of the most popular methods to measure distance, structure, association, and dynamics at the single molecule level. However, major challenges are limiting FRET in several fields of physical and analytical sciences: (i) a short distance range below 8 nm, (ii) a concentration range in the nanomolar regime, and (iii) generally weak detected signals.At the interface between physical chemistry and nano-optics, the proposal objective is to extend the effectiveness of single molecule FRET using plasmonic nanocircuits to: (i) perform FRET on a range up to 20 nm, (ii) detect a single FRET pair in a solution of micromolar concentration, and (iii) improve the statistical distribution in FRET measurements.To meet its ambitious goals, the proposal introduces plasmonic nanocircuits to tailor the light-molecule interaction at the nanoscale. Energy transfer between donor and acceptor fluorophores is efficiently mediated through intense surface plasmon modes to extend the FRET distance range and improve the fluorescence signal. Moreover, the nanocircuits will be combined with recent innovations in biophotonics: stimulated emission of acceptor fluorescence, full dynamic analysis, and fluidic nanochannels.The scientific breakthroughs and project impacts will open new horizons for proteomics, enzymology, genomics and photonics. For elucidating molecular structure, the long range FRET will enable understanding the folding structure of large DNA or protein molecules. For assessing chemical reactions, achieving single molecule analysis at micromolar concentration is essential to monitor relevant kinetics, reveal sample heterogeneity, and detect rare and/or transient species. For analytical chemistry, nanocircuits are ideal for sensitive biosensing on a chip. For photonics, nanocircuits can realize key components for optical information processing at the nanoscale.