A number of NLO polymers were obtained, in which aromatic polyester is a matrix and the chromophores are incorporated into the form of a side chain. Special monomers are based on 2,2-bis(3-amino-4-hydroxyphenyl)propane; they contain an azomethine bond and various electron-acceptor groups (nitro, cyanide, and fluoride) as substituents in the side-chain aromatic ring. The effect of the type of the electron-acceptor substituent, its substitution position in the aromatic ring with respect to the azomethine bond, and special monomer concentration on the optical, mechanical, and thermal properties of the whole system was studied.