The synthesis of homoditopic heterocomplementary monomers forming sextuple hydrogen-bond-mediated self-assemblies in apolar solvents is described. The nanostructures of the fibrillar aggregates formed in decane solutions of such monomers were investigated by small-angle neutron scattering. The fibers were found to be rigid, with an average length that increases upon increasing concentration and/or decreasing temperature. The cross section and the mass per unit length of the fibrillar aggregates are constant in the explored concentration range spanning both the dilute and semidilute regimes. These parameters are also insensitive to a temperature change. From the values of the cross section and of the mass per unit length, it can be inferred that the fibers contain on the average several monomolecular wires.