We report the synthesis of all-conjugated branched poly(thiophenes) with a control over the degree of nonlinearity via two different routes. In the first approach a branched monomer is polymerized using three different catalysts which differentiate in the degree of association to the a-system of the polymer backbone. In the second approach a copolymerization is performed with the branched and a linear monomer. In a next step the influence of the different degrees of nonlinearity on the optoelectronic properties is investigated by UV-vis and fluorescence spectroscopy. Finally, the thermal behavior, the morphology, and the electrical properties at the nanoscale of the material in solid state are studied using DSC and AFM techniques.