Hexathiophene occupies a place of relevance in the context of organic semiconductors employed as active layers in opto-electronic devices. The knowledge of the structure of this class of materials in the film-phase is crucial for understanding and tailoring the performances of these devices. Here, thin films of hexathiophene have been deposited on silica by organic molecular beam deposition under controlled growth conditions. The structure of these films has been investigated by transmission electron diffraction compelling evidences of the presence of a structure different from the bulk phase. (c) 2005 Elsevier B.V. All rights reserved.