This manuscript describes the dendritic macromolecules for optical and optoelectronic applications, particularly stimulated emission, laser emission, and nonlinear optics. Dendrimers have been designed and synthesized for these applications based on simple concepts. A core-shell structure, through the encapsulation of active units by dendritic branches, or a cone-shaped structure, through the step-by-step reactions of active units, can provide particular benefits for the optical high-gain media and nonlinear optical materials. It also described experimental results that support the methods presented for designing and fabricating functionalized dendrimers for optoelectronic applications, and theoretical results that reveal the intermolecular electronic effect of the dendritic structure.