This study focuses on the modular synthesis of a new class of nonionic dendritic amphiphiles and their behavior at the water air interface. Our approach is based on a modular architecture consisting of two different generations of hydrophilic polyol dendrons connected to a two-chain hydrophobic block. Caused by different polarities of polyol I and aliphatic groups, the molecules are surface-active and, by analogy to phospholipids, can form well-organized Langmuir monolayers at the water surface. The self-association process and phase behavior of these molecules with two different headgroup sizes were investigated by means of surface pressure and surface potential area isotherms by surface shear rheology and Brewster angle microscopy. With these techniques, we were able to observe marked differences in the phase behavior of the two molecular generations.