Several graphene nanoribbon forms have been obtained from the fusion of different molecular precursors over the last decade. These include a rich set of examples in which heteroatoms substitute carbon at precisely defined sites. Considering this scenario, we employed first-principles calculations to study the electronic and transport properties of coronene-based nanoribbons with boron and nitrogen heteroatoms. We demonstrate that B/N substitution induces marked changes in the electronic properties of these structures in comparison to the full-carbon counterpart. For instance, the systems change from semiconductor to metallic due to levels introduced by the heteroatoms. In addition, non-trivial spin-polarized distributions emerge in selected cases, resulting in systems with a high potential for insertion in spintronic applications. This is further investigated in nanojunctions composed of N-substituted electrodes.