The synthesis of rigid-rod poly([1.1.1]propellane)s and poly(p-phenylene)s with hydroxy functionalities in the side chains is described. The suitability of these hydroxy functions as anchor groups for dendritic fragments is investigated. Initial experiments show that not only oligophenylenes as model compounds but also the polypropellane can be dendrimerized to a high degree of conversion. The rigidity of the backbones is considered important in regard to this matter and is therefore addressed theoretically. Molecular modelling calculations based on the AMBER 3.0 force field show that, in fact, the polypropellane backbone is considerably rigid.