Abstract A new class of push–pull spirobifluorene compounds 1–5 has been synthesized. The nonlinear optical (NLO) properties (first and second hyperpolarizability β and γ, respectively) of spirobifluorene derivatives have been investigated forthe first time using electric field induced second harmonic (EFISH) and third harmonic generation (THG) methods. Moreover, a comparison with the corresponding push–pullfluorene monomers ...
