This review article describes recent developments in the field of second-order nonlinear optical (NLO) polymers with specific focus on their characterization methods, materials synthesis, chromophore orientation techniques, and device applications. For the characterization techniques of NLO properties of organics and polymeric materials, electric field-induced second harmonic generation, hyper-Raleigh scattering, electro-optic coefficient measurement, etc. are discussed. The significant progress obtained from the authors’ investigations, resulted in various types of polymeric materials including dendrimers and organic-inorganic hybrids with specific structures of academic and technological significance which are presented here. To produce highly efficient macroscopic nonlinearity in NLO polymeric systems, several chromophore orientation techniques such as static field poling, photoassisted poling, all optical poling, contact and corona poling are also demonstrated. In addition, the prospects for practical applications of the NLO polymers in information technology are reviewed.