Specific peptide sequences designed by inspection of protein-protein interfaces have been identified and used as tectons in hybrid functional materials. Here, an 8-mer peptide derived from an interface of the peroxiredoxin family of self-assembling proteins is exploited to encode the assembly of the perylene imide-based organic semiconductor building blocks. By augmenting the peptide with additional functionality to trigger aggregation and manipulate the directionality of peptide-semiconductor coupling, a series of hybrid materials based on the natural peptide interface is presented. Using spectroscopic probes, the mode of self-assembly and the electronic coupling between neighboring perylene units is shown to be strongly affected by the number of peptides attached, and by their backbone directionality. The disubstituted material with peptides extending in the N to C direction away from the perylene core exhibits strong coupling and long-range order, both attractive properties for electronic device applications. A bio-organic field-effect transistor is fabricated using this material, highlighting the possibilities of exploiting natural peptide tectons to encode self-assembly in other functional materials and devices.