Since its inception in 2007, the Colloidal Materials Group, one of the research groups in nanotechnology of the Institute of Chemistry of São Carlos (IQSC) at University of São Paulo (USP) carries out studies related to the development of syntheses methods of nanoparticles and multifunctional nanostructured systems. Our works search new synthesis methodologies that allow high size and shape control of the individual nanoparticles or that compose the nanostructured systems and has as a principle the synthetic approaches based on the modified polyol and thermal decomposition processes. Systems involving nanoparticles have received extensive attention both in the fundamental research and in several technological applications exploring the unique properties presented in nanomaterials. These properties are strongly size- and shape-dependent of the nanoparticles and a large distribution of size or shape implies in a high response dispersion, justifying the intense research for the so-called nanoparticle monodisperse systems. In this review, we present the main aspects to obtain monodisperse nanoparticulate systems, correlating with the synthesis processes used in our group and some of our results in systems involving nanoparticles with magnetic, optical, and electronic properties, as well as some obtained composite materials for different applications.