Highly ordered adlayers of three calix[4]arene derivatives have been prepared on Au(111) surface in HClO4 solution. The adlayer structures are characterized by in situ scanning tunneling microscopy (STM). High-resolution STM images reveal the molecular orientation and packing arrangement in the ordered adlayers. All the molecules are upright on Au(111) surface in pinched cone conformation. The structural difference of these molecules is proposed to be from the different functional groups at the upper and lower positions. The structural models are tentatively proposed for three ordered adlayers. (C) 2002 Elsevier Science B.V. All rights reserved.