The development of composites based on carbon fillers led to outstanding progress in various technologies over the past decade. Major importance was attributed to the proper selection of polymer and filler pairs, but also to the aspects derived from interfacial interactions and filler dispersion within the polymer medium. These factors are known to have a great impact on the performance of the designed multiphasic material. In this work, two categories of composites made of distinct polymers and carbon nanotubes were studied, emphasizing the effect of polymer matrix features on electrical properties. The first system was obtained based on a polyimide precursor that has a semi-flexible and non-symmetric structure, in which variable amounts of carbon nanotubes were incorporated. For comparison reasons, another system containing carbon nanotubes was proposed, which has as a matrix with a new polysulfone (PSF) structure. The latter was obtained via chlorometilation reactions, and subsequently via oxidation reactions and the acetalization of poly(vinyl alcohol) (PVA), rendering a PSF with PVA side chains. Each prepared composite system was investigated via molecular modeling, evidencing the effect of the polymer matrix on the overall Waals-surface-bounded molecular volume and polarizability. The dielectric constant of the polymer was determined either from theoretical calculations or from broadband dielectric spectroscopy experiments. Also, another important parameter obtained in this work was electrical conductivity. It was found out that conduction characteristics are affected by the amount of carbon nanotubes inserted in the polymer matrix. On the other hand, it appears that the structural features of the polymer have led to different conductivity values. All these results are relevant for making polymer-derived components for electronics.