|The research reported in this thesis focused on poly(propylene imine) (PPI) dendrimers, in terms of their structures, properties and potential applications. Different analytical techniques, including our main research tool, NMR spectroscopy, as well as AFM imaging and UV-vis spectroscopy, were used for the elucidation of structural information. The study showed (1) PPI dendrimers tend to have the extended chain conformation in polar solvents because of the strong interaction between solvent and dendrimer molecules, while in nonpolar solvents the dendrimers are inclined to have the back-folded chain conformation as a result of the weaker interaction between solvent and dendrimer molecules; (2) Inverse micelles between PPI dendrimers and long chain aliphatic acids can be formed successfully and spontaneously through self-assembling in both polar and nonpolar solvents, and the self-assembled inverse micelles have different morphologies in different solvents; (3) PPI dendrimers have shown to have catalytic properties in the hydrolysis of esters under quite mild conditions, e.g., slightly basic solution and room temperature. The role of dendrimers in this catalysis may be as a template to orient the reactants in optimized positions for the hydrolysis reactions. The mechanism of this catalysis is still under investigation.