Viscoelastic properties of several multiphase polymeric materials were investigated in connection with their morphologies. Both mechanical modeling and mechanical spectrometry were used as tools for extracting information about morphology, molecular mobility, and interfacial interactions in such heterogeneous systems. The use of self-consistent mechanical models in direct and reverse modes was shown to be of interest for in depth discussion of the possibilities and limitations of the theoretical mechanical approach in the understanding of experimental dynamic mechanical data of complex polymeric materials. Christensen and Lo's model was used in direct mode to highlight mechanical coupling effects in binary thermoset/thermoplastic polymer blends. It was shown that the magnitude of these effects between phases in such blends, as in composite materials, depends not only on mechanical properties and relative content of each phase but also on the geometric arrangement of the polymeric phases. Furthermore, a new way of presenting experimental dynamic mechanical data and simulations resulting from direct mechanical approach, was also proposed as a qualitative, well-suited probe of morphology of multicomponent polymeric materials. The models of Christensen and Lo and of Herve and Zaoui were both used in reverse mode. It was demonstrated that such a new approach for mechanical modeling allows the extraction of the actual viscoelastic properties of one phase among others in multiphase polymeric materials. That is of particular interest for investigating the actual properties of the interfacial area in such complex systems, whose experimental in situ detection and characterization remain problem.