Copolymers of methyl methacrylate and chromophores with methacrylate end groups were obtained by radical polymerization. Their nonlinear optical properties ware examined by electric field induced second-harmonic generation (EFISH) measurements and compared with corresponding monomeric dyes. All of them had maximum absorption wavelengths between 480 and 510 nm. Values for μβ (dipole moment μ, molecular hyperpolarizability β) were remarkably high and reached 530 10 - 6 8 Cm 5 V - 1 . According to quantum chemical calculations (ab initio and semi-empirical) increasing the acceptor strength in going from the dicyanovinyl to the dicyanomethyleneamino moiety also leads to an increase in the molecular hyperpolarizability. In contrast, further increasing the acceptor strength to the tricyanovinyl group is accompanied by a levelling off or, even, a decrease in the calculated β-value.