A novel chain structure made of gold adatoms and gold-thiolate complexes on Au(111) is predicted here by first principles density functional theory. In this structure, the CH3S-Au-SCH3 complexes are parallel to each other and linked together by interactions between Au adatoms and Au atoms in the complexes as well as by bonding between the Au adatoms and the CH3S-groups in the CH3S-Au-SCH3 complexes. This new structure is compared with previously proposed gold-thiolate polymers on Au(111) and found to be energetically competitive with previous models at both low and high coverages. (c) 2009 Elsevier B.V. All rights reserved.