A series of dendron-modified nonlinear optical (NLO) chromophores and multiple chromophore-containing crosslinkable NLO dendrimers have been developed. The enhancement of poling efficiency (40%) in the dendritic NLO chromophore/polymer guest/host system was obtained due to the significant minimization of intermolecular electrostatic interactions among chromophores by the dendritic effect. Multiple NLO chromophore building blocks can be further placed into a dendrimer to construct precise molecular architecture with predetermined chemical composition. The site-isolation effect, through the encapsulation of NLO moieties by dendrons, can greatly enhance the performance of electro-optic (E-O) materials. A very large E-O coefficient (r33=60 pm/V at 1.55 micrometers ) and high temporal stability (85 degree(s)C for more than 1000 h) were achieved in a NLO dendrimer developed through the double-end functionalization of a 3D shape phenyl-tetracyanobutadienyl (Ph-TCBD)- containing NLO chromophore with thermally crosslinkable trifluorovinylether-containing dendrons.