Since the beginning of its modernization at the end of the XVIII century, Chemistry has been developed continuously through the atomic-molecular theory; however, the chemistry of the covalent bond has been exploited until its conceptual limits, so even the best synthetic chemist nowadays can not build complicated molecular systems only using the tools available to create covalent bonds. Due to the next step in growing the level of complexity to organized polimolecular systems present in living systems is linked to non-covalent interactions, is the moment for chemists to look beyond the classic synthesis to Supramolecular Chemistry, a young brand of science that studies the basic features of these non-covalent interactions.
          In the last 25 years, a big part of the chemical research has stopped in the field of photoactive molecular devices, finding that the results that can be obtained from the interaction of light with matter depend on the level of organization of matter; in this sense, supramolecular entities that contain these type of components can exhibit new properties modulated by the position of their constitutional units, so that the photochemical processes achieved by these species can be considered distinctive. Throughout this route is possible to arrange molecular components previously obtained that carry out certain properties related to light, being possible to design integrated organized systems capable to elaborate the signal provided by photons to develop complex functions.
          The family of synthetic hosts called Cucurbit[n]urils (CB[n]), whose name is related to the pumpkin-like shape of these organic capsules in which the central diameter is broader than the portals flanked by urea carbonyl groups, have some properties that suggest its potential in Nanotechnology as components of molecular machines, being the main reason their ability to encapsulate guest molecules reversibly by changing the experimental conditions so that we can change their properties. This behaviour make them being positioned to compete with cyclodextrins (CDs) as platform in applications at industrial scale.
          Based on these principles, the present work establishes the differences in the processes of complexation in the case of cucurbit[n]urils and cyclodextrins with some tricyclic dyes used as models of photoactive molecules, comparing the acid-base properties of the free and complexed dyes and the binding constants of the same molecules in their ground and singlet excited electronic state. Moreover, it has been described the photophysical and photochemical effects of such processes of complexation by measuring parameters like fluorescence quantum yields and lifetimes of the singlet excited states, which have been used to elaborate a library of supramolecular systems able to response as double fluorimetric-colorimetric sensor in the detection of some families of organic compounds with several functional groups, exploting it mainly in the recognition of amines and ammonium salts with different number of substituents and number of carbons.
          By the other hand, in this text we describe the mechanism of interaction of the different CB[n] with the 2,4,6-triphenylpyrylium cation as photoactive molecule with photosensitizing and photoactive properties, defining the photochemical and photophysical changes associated to the incorporation of the organic cation inside these organic capsules used to measure the values of the binding constants of the complexation processes of the ground and excited electronic state of the triphenylpyrylium ion. Through a theoretical study we could support the experimental results obtained by analysing the crystal structure of the prepared complexes, and describing the photophysical properties and the photoinduced electron transfer processes of the triplet excited states of the different complexes it is possible to prepare electroluminescent devices.
Finally, the work presented here includes the process of incorporation of gold nanoparticles in the void or the organic capsule of CB[7] as a procedure to stabilize them from their aggregation, proving that the metallic nanoparticles are occluded in the cavity by using analytical techniques such as Analytical Microscopy and Positron Annihilation Spectroscopy. Such studies let us know the steric restrictions that have been imposed by these macrocyclic structures to different substancies that interact with the surface of gold nanoparticles. At the end of this study, it has been obtained for the first time the transient spectrum due to the species formed after the absorption of light by the surface plasmon band characteristic of these kind of materials, opening the way to search for the photocatalitic properties that could be exhibited by gold nanoparticles encapsulated inside the cavity of cucurbit[n]urils.