A novel and rapid approach for the synthesis of aliphatic polyamide dendrimers, consisting of the 3,4-dialkoxyhydrocinnamamide structure as a repeating unit, has been developed. Aliphatic polyamide dendrons and dendrimers were easily prepared by a convergent approach involving activation of a carboxylic acid at the focal point using (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (DBOP) as the activating agent, followed by condensation with an unprotected AB,, building block. Dumbbell-shaped and star-shaped third generation dendrimers were prepared from the third generation dendron and core molecules containing two or three functional groups. All the above products could be purified only by precipitation, and their structures were confirmed by H-1 NMR, IR, and matrix-assisted laser desorption ionization time-of-flight mass (MALDI-TOF-MS) spectroscopies and elemental analysis.