The properties of graphene nanoribbons are highly dependent on structural variables such as width, length, edge structure, and heteroatom doping. Therefore, atomic precision over all these variables is necessary for establishing their fundamental properties and exploring their potential applications. An iterative approach is presented that assembles a small and carefully designed molecular building block into monodisperse N‐doped graphene nanoribbons with different lengths. To showcase this approach, the synthesis and characterisation of a series of nanoribbons constituted of 10, 20 and 30 conjugated linearly‐fused rings (2.9, 5.3, and 7.7 nm in length, respectively) is presented.

Singlet fission has emerged as a promising strategy to avoid the loss of extra energy through thermalization in solar cells. A family of dimers consisting of nitrogen‐doped pyrene‐fused acenes that undergo singlet fission with triplet quantum yields as high as 125 % are presented. They provide new perspectives for nitrogenated polycyclic aromatic hydrocarbons and for the design of new materials for singlet fission.

Star‐shaped nanographenes (SNGs) are large monodisperse polycyclic aromatic hydrocarbons that are larger than a nanometer and have shown a lot of promise in a wide range of applications including electronics, energy conversion, and sensing. Herein, we report a new family of giant star‐shaped N‐doped nanographenes with diameters up to 6.5 nm. Furthermore, the high solubility of this SNG family in neutral organic solvents at room temperature allowed a complete structural, optoelectronic, and electrochemical characterisation, which together with charge transport studies illustrate their n‐type semiconducting character.