We prepared third-generation amphiphilic dendrons 3-14 and 3-18 consisting of a hydrophilic aliphatic polyether dendritic core and either tetradecyl or octadecyl peripheries, respectively. Their solid-state self-assembly behavior was investigated by comparison with 3-22 having the same dendritic core and longer docosyl peripheries. In marked contrast to the lamellar assembly of 3-22, small-angle X-ray analysis suggested that 3-14 and 3-18 show oblique columnar structures with presumably elliptical cross sections. The observed results can be rationalized by dendron shape anisotropy, which is strongly associated with the degree of crystallization as a function of alkyl chain length. (c) 2007 Wiley Periodicals, Inc.