This work describes a strategy to create terthiophene (3T) naphthalenediimide (NDI) nanostructures via the β-sheet selfassembly of a functionalized dipeptide. The dipeptide assembles into 1D nanofibers in organic solvents and forms a self-supporting organogel at low concentrations in CH 2 Cl 2 . The nanostructures engage in extensive intermolecular ππ stacking interactions.An important challenge in organic materials is to be able to program small and molecular building blocks to precisely assemble into multiscale and multifunctional superstructures that capture, transport, and process various forms of energy.1 Predictable strategies to create segregated and bicontinuous arrays of interpenetrating donor (D) and acceptor (A) chromophores are needed to optimize charge separation and transport within optoelectronic materials.2 Thus, the 1D self-assembly of DA molecules is emerging as a potential strategy to tune the properties of thin film materials and devices. 3 The cofacial π-stacking interactions that often comprise such nanostructures are thought to provide pathways for charge transport and energy migration and are expected to produce maximal charge carrier mobilities. 4 Although considerable progress has been realized over the last several years, precise control of the interactions of chromophores within self-assembled nanostructures remains difficult.Hydrogen-bonddriven self-assembly offers a directional strategy to predictably organize D and A chromophores over long distances and has recently led to new functional electronic materials.5 Peptide-based β-sheet aggregation provides a modular method to construct well-defined nanostructures that are stabilized by intermolecular hydrogen-bonding interactions.6 Notably, we have developed strategies based on peptide β-sheet formation and amphiphilic self-assembly in water to create a variety of 1D nanostructures ranging from nanotubes 7 to 1D fibers and ribbons 8 from very simple building blocks. This design strategy is based on prior studies demonstrating the selfassembly of a series of dilysine peptides functionalized at the ε-amino position with a single naphthalenediimide (NDI) chromophore in water. For example, the β-sheet self-assembly of a series of dilysine peptides functionalized at the ε-amino position with a single NDI chromophore produced nanofibers and nanoribbons in water.8d These dipeptide sequences reflect an alternating polar and nonpolar amphipathic pattern, which is commonly observed in natural and isolated synthetic, antiparallel β-sheet structures.9 The self-assembly strategy further capitalizes on an aromatic chromophore to drive aggregation via hydrophobic effects and ππ stacking interactions in aqueous media. Time-resolved fluorescence anisotropy experiments have shown that efficient energy migration occurs within the resultant π-aggregated NDI assemblies. 7c,10 This strategy was versatile with respect to the N-terminal substituent. For example, an Fmoc chromophore appended to this position of the dipeptide affords a hydrogel comprising ...