Molecular adsorption on both quasicrystalline and approximant substrates has produced a number of pseudomorphic films, and has led to a deeper understanding of the chemistry of the surfaces of these materials. Here, the recently reported reconstructed (111) surface of the 1/1 Au-Al-Tb Tsai-type approximant has been used as a template for pentacene (Pn) adsorption, which is investigated using scanning tunneling microscopy. This surface provides unique varieties of adsorption sites compared to a normal metal surface. After room-temperature deposition, the Pn molecules are mobile yet exhibit a structure which indicates a bond with the Tb atoms of the surface, while reflecting the twofold symmetrical nature of the reported Au/Al row reconstruction. Postdeposition annealing shows a linear arrangement of molecules in a specific adsorption geometry, likely corresponding to the most favorable energetic configuration.