After a historical description of the different families of porous compounds and their synthesis pathways, the paper describes a particular system, the ULM series, and the correlation between the evolution of the pertinent chemical parameters and the structure of the resulting materials. The hypothesis for a possible mechanism of formation of these porous solids is tested both by in situ experiments (NMR and synchrotron radiation) in hydrothermal conditions and from the examination of its possible consequences, principally in the domain of magnetic porous compounds. The analysis of its limits leads to a new family of composite inorganic-organic porous solids in which organic and inorganic parts participate in the framework.Partant de l'histoire chronologique de la decouverte des diverses familles de composes microporeux, l'article examine les divers types de synthese qui y conduisent avant d'examiner comment, sur un systeme chimique precis, la serie des ULM, l'etude systematique de la correlation entre l'evolution des parametres chimiques et la structure des solides correspondants permet d'etablir une hypothese de mecanisme de formation. Sa validite est testee soit a partir d'etudes in situ (RMN et rayonnement synchrotron) en conditions hydrothermales, soit par l'examen de ses consequences previsibles, en particulier dans le domaine des microporeux maggetiques. L'analyse de ses limites conduit a proposer une nouvelle famille de microporeux composites dans lesquels parties minerales et organiques participent a l'edification du squelette poreux.