Recent progress in developing highly efficient nonlinear optical dendrimers and polymers for high-performance electro-optic (EO) devices has been reviewed. Our efforts are focused on using nanoscale architectural control to tailor the size, shape, conformation, and functionality of NLO chromophores and macromolecules and Studying their effects on poling efficiency. The structures of these materials vary from a 3-D-shaped dendritic chromophore, multifunctional dendrimers with the center core connected to NLO chromophores and crosslinkable functional groups at the periphery, to side-chain-dendronized NLO polymers. All the poling results from these systems have shown dramatically enhanced EO properties (a factor of 2-3) compared to conventional NLO polymers.