Dendrimers containing rigid conjugated backbones were prepared by a convergent method where the attachment of dendritic branches and the extension of phenylene-ethynylene units were alternatively manipulated on the structure of AB₂ substituted phenylacetylene in a combination with Suzuki-Miyaura and Sonogashira cross-coupling reactions. These dendrimer structures were applied for the construction of several light-harvesting antennas and charge-separating systems. The conjugated network inside the dendritic structure was shown to play an important role as a mediator in both the photoinduced energy- and electron-transfer processes. In addition, we describe a novel methodology for the stepwise construction of shape-persistent assemblies using the dendrimers with conjugated backbones as the key modular building blocks. These examples demonstrate advantage of the dendrimer with conjugated backbones for the construction of nanoscale molecular devices such as artificial photosynthetic systems.