The bottom-up synthesis of all-carbon graphene nanoribbons (narrow strips of sp2 hybridized carbon) has attracted much attention in recent years, with a number of contemporary demonstrations of the preparation of all-carbon systems. However, fewer studies have focused on the solution-phase synthesis of heteroatom-doped graphene nanoribbons, the preparation of which remains a significant synthetic challenge. We have developed new synthetic methodologies for the synthesis of oligobenzoquinolines via the aza-Diels–Alder (Povarov) reaction, as well as strategies for controlling the length and sequence of these precursors. Our straightforward approach also provides access to crowded macromolecular polybenzoquinoline scaffolds with a unique architecture and connectivity, which are key intermediates for the preparation of nitrogen-doped nanoribbons. These findings hold implications for the bottom-up synthesis of graphene nanoribbons whose edge character, terminal functionalities, doping, and length are precisely controllable.