The nonlinear optical material is a general term for the materials efficiently make appearance of nonlinear phenomenons optically as the responses to optical wavelength conversion, optical amplification as well as the refractive index changes due to its intensity. Nonlinear optical materials are largely divided into inorganic and organic materials. In 1930, the nonlinear optical effect related to optical wavelength conversion was predicted, which was said to be the first finding knowledge about the nonlinear optical phenomenon. In 1960, laser oscillation using inorganic material was reported. Since then researches of inorganic nonlinear optical materials were actively taken place, but now-a-days, probably there is no more that undiscovered.
On the other hand, the 1982 ACS symposium report added momentum to the organic nonlinear optical material studies. Since then the studies have started to become active. It revealed organic compounds with the delocalized conjugated electrons which have excellent nonlinear optical property and high-speed responsiveness due to high mobility of electrons.
The 21st Century is said to be an age of photonics. As one of the basic technology of photonics, improvements of the wavefront control technology using organic nonlinear optical effects are considered very important. Now R&D on the organic materials with excellent nonlinear optical properties, and vigorous applied studies have been carried out.

A0621	A1251	A0794
A0838	C0943	C0214
C1209	C1349	D2020
D2263	D2505	D0289
D2135	H0747	M0997
M0999	M0909	M0985
M1677	N0529	N0527
M0953	N0117	N0118
N0119	N0400	N0547
N0546	N0540	N0281

Purification just before use is recommended.