Self-organization of individual dendronized poly(phenylacetylene) (PPA) macromolecules on highly oriented pyrolytic graphite (HOPG) is revealed by atomic force microscopy (AFM). The dendronized PPA is composed of amphiphilic, self-assembling dendrons. Individual macromolecules are imaged as oblate cylindrical objects whose relative orientation in the first layer adsorbed to the HOPG reflects underlying lattice symmetry. This is due to epitaxial adsorption of the peripheral alkyl tails. Thermal annealing results in large domains of uniformly oriented dendronized PPAs (i.e., 2D nematic order) due to intermolecular interactions. Periodicity within domains and between layers is dictated by the height and width of the oblate cylindrical PPA. A further consequence of epitaxy is that at the HOPG interface the PPA backbone adopts a more extended conformation than the helical cis-cisoidal conformation of the internally ordered hexagonal columnar (Phi(io)(h)) phase found in bulk. Well-ordered domains of cylindrical helical dendronized PPAs offer the potential to exploit single-handed helical chirality at the HOPG surface.