Abstract
In this mini-review, recent progress of the evaluation of the first hyperpolarizability (β) and the second hyperpolarizability (γ) by hyper-Rayleigh scattering (HRS) or second harmonic scattering (SHS), and higher-order HRS or third harmonic scattering (THS) as well as their brief history are described. Furthermore, we report the recent progress in the development of nonlinear optical (NLO) chromophores by using HRS.