With the rapid development of optical communication and optical information processing technology, nonlinear optical materials have attracted considerable attention in both industry and academia. Compared with inorganic non-linear optical materials, organic nonlinear optical materials exhibit the advantages of short response time, easy processing, and high nonlinear coefficient. Particularly, 4-N, N-dimethylamino-4’-N’-methyl-stilbazolium tosylate (DAST) is an artificially-designed organic non-linear material with non-centrosymmetry and strong polarizability. Numerous theoretical and experimental results indicated that DAST is one of the most important and successful organic nonlinear materials. Owing to its high second-order optical nonlinear coefficient, large electro-optic coefficient, large birefringence difference, and low dielectric constant, faster and stronger optical nonlinear responses can be achieved by DAST. Recent spectroscopic results revealed that DAST exhibits anisotropic THz spectral features. In this article, the growth of DAST crystals, and their practical applications in THz wave generation, second harmonic generation, as well as electro-optical detection and electro-optical modulation, are systematically reviewed. Moreover, our recent results about the preparation of DAST-based composite films, THz spectra, optoelectronic properties of DAST modified by carbon nanotubes or graphenes, and novel DAST-based metamaterials, are simultaneously presented. These results suggest a new perspective on DAST and its potential applications in the future. In addition, we have proposed some new ideas about DAST, such as DAST crystal growth induced by an electric filed or self-assembling monolayer, and frequency conversion efficiency of DAST crystal improved by quasi-phase-matching method. The DAST results systematically summarized in this review are helpful for promoting further studies on DAST-based materials and their applications in electro-optic modulators, THz detectors, frequency converters, etc, and consequently, the applications of DAST in optical communications, optical information processing, military technology and other important fields can be further expanded.