Macromolecular engineering allows the introduction of targeted functionalities in polymer architectures. Our research focus on the development of such materials with applications in the field of organic electronics. Independently of the targeted applications, the structural characteristics of the polymers are essential for enhanced performance. Two case studies will be presented highlighting the correlation between the structure and the functional properties. On one hand organic devices based on polymers could offer an efficient path for the production at low cost of energy harvesters particularly adapted for nomadic applications. Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films doped with p-toluenesulfonate molecules are considered as promising thermoelectric materials and an important improvement of the thermoelectric properties of PEDOT thin films was obtained through structural engineering. A clear relationship between the crystalline structure and the electrical and thermoelectric properties was consequently derived for such type of conducting organic materials. On the other hand block copolymers are a unique class of materials which self-assemble into periodic structures at the nanometer scale with a range of controllable morphologies. Their self-assembly into nanostructured thin films offers a promising route to provide a significant advancement in technological applications such as lithography, non-linear optics or ultrafiltration. Over the last years we have developed a first generation of lithographic materials based on the directed self-assembly of PMMA-b-PS and highlights on their use in lithographic applications will be presented. Additionally we have designed new block copolymer systems characterized by higher segregation strengths and more complex architectures which allow the definition of sub-20 nm features with exquisite symmetries. A few anecdotes related to their thin film self-assembly and their segregation behavior as regards to the processing parameters will be discussed.