"In this project (FENASY), we wish to study fast (picosecond regime, ps) and ultrafast (femtosecond regime, fs) dynamics of some (guests) porphyrins derivatives in solutions and confined in chemical and biological nanocavities and nanochannels provided by cyclodextrins, Human Serum Albumin protein, and MCM-41 zeolite. The guests and hosts are being used in different fields of Science and Technology. We will interrogate their photoreaction and relaxation dynamics and study the effect of nanoconfinement on the related and subsequent elementary events at both ps and fs time scales. Powerful techniques based on ultrafast laser and single molecule technologies will be our tools to carry out FENASY. We will then focus on studying the relationship between the photodynamics (time domain) and nature and size of the formed nanostructure (space domain, nano to micrometer domain). The expected results will allow explaining the relaxation behaviour of these important molecules upon excitation to Soret and Q- bands, and the relationship to their photochemistry in solution and for the first time within chemical and biological nanocavities and nanochannels. We believe that the expected results will be of great interest to the scientific community in designing new derivatives of these and other systems for use in nanotechnology (nanoLED’s, nanostwitches, etc), nanodrugs (nanophotodynamics therapy of cancer), and environmental science (heavy metal nanocleaning). Key words. Femtochemistry, single molecule fluorescence microscopy, porphyrins, nanocavity, cyclodextrins, protein, zeolites, dynamics, emission, absorption, nanotechnology, biotechnology, environmental science, photodynamic therapy."