C. Nmr, Synthesized from 29 (346 mg; 2 mmol) and 12 (375 mg; 2.5 mmol) following the general procedure A. Yield: 321 mg (81 %); white solid; R f = 0SiO 2 ; CH 2 Cl 2 /EtOAc 10:1); mp 192?193 °C; 1 H NMR (CDCl 3 , 300 MHz): ? = 2.81 (s, 3H) (s, 2H), 10.09 ppm (s, 1H), pp.90-131

2. Hz and . Nmr, 75 MHz): ? = 123, pp.1673-1674

T. Taniuchi, S. Ikeda, S. Okada, and H. Nakanishi, Tunable Sub-Terahertz Wave Generation from an Organic DAST Crystal, Japanese Journal of Applied Physics, vol.44, issue.No. 21, pp.652-654, 2005.
DOI : 10.1143/JJAP.44.L652

A. Schneider, M. Neis, M. Stillhart, B. Ruiz, R. U. Khan et al., Generation of terahertz pulses through optical rectification in organic DAST crystals: theory and experiment, Journal of the Optical Society of America B, vol.23, issue.9, pp.1822-1835, 2006.
DOI : 10.1364/JOSAB.23.001822

Z. Yang, L. Mutter, M. Stillhart, B. Ruiz, S. Aravazhi et al., Large-Size Bulk and Thin-Film Stilbazolium-Salt Single Crystals for Nonlinear Optics and THz Generation, Advanced Functional Materials, vol.23, issue.13, pp.2018-2023, 2007.
DOI : 10.1002/adfm.200601117

X. Che, J. Vallet, F. Bure?, and B. Caro, Robin-le Guen, F. Dyes Pigm, pp.562-570, 2015.

. Chem, S. Soc-achelle, C. Baudequin, S. Achelle, N. Plé et al., Targets Heterocycl. Syst, J, vol.127, issue.1, pp.7282-7283, 2005.

P. Bao and Z. Yu, Restricted Geometry Optimization:?? A Different Way To Estimate Stabilization Energies for Aromatic Molecules of Various Types, The Journal of Physical Chemistry A, vol.111, issue.24, pp.5304-5313, 2007.
DOI : 10.1021/jp067440i

H. Pan, X. Gao, Y. Zhang, P. N. Prasad, B. Reinhardt et al., A New Class of Heterocyclic Compounds for Nonlinear Optics, Chemistry of Materials, vol.7, issue.5, pp.816-821, 1995.
DOI : 10.1021/cm00053a002

S. I. Kotelevskii, O. V. Prezhdo, T. M. Krygowski, H. Szatylowicz, O. A. Stasyuk et al., Aromaticity indices revisited: refinement and application to certain five-membered ring heterocycles, Tetrahedron, vol.57, issue.27, pp.5715-5729, 2001.
DOI : 10.1016/S0040-4020(01)00485-9

F. Bure?, H. ?ermáková, J. Kulhánek, M. Ludwig, W. Kuznik et al., Structure-Property Relationships and Nonlinear Optical Effects in Donor-Substituted Dicyanopyrazine-Derived Push-Pull Chromophores with Enlarged and Varied ??-Linkers, European Journal of Organic Chemistry, vol.443, issue.3, pp.529-538
DOI : 10.1002/jlac.198819881217

C. Hadad, S. Achelle, J. C. García-martinez, J. Rodríguez-lópez, R. Lartia et al., 4-Arylvinyl-2,6-di(pyridin-2-yl)pyrimidines: Synthesis and Optical Properties, The Journal of Organic Chemistry, vol.76, issue.10, pp.3837-3845, 2011.
DOI : 10.1021/jo200204u
URL : https://hal.archives-ouvertes.fr/hal-00875496

C. Reichardt, Solvatochromic Dyes as Solvent Polarity Indicators, Chemical Reviews, vol.94, issue.8, pp.2319-2358, 1994.
DOI : 10.1021/cr00032a005

C. G. Bethea, (c) Ledoux, I.; Zyss, Appl. Phys. Lett. J. Chem. Phys, vol.24, issue.213, pp.445-447, 1974.

Z. H. Li, M. S. Wong, Y. Tao, and M. Iorio, Synthesis and Functional Properties of Strongly Luminescent Diphenylamino End-Capped Oligophenylenes, The Journal of Organic Chemistry, vol.69, issue.3, pp.921-927, 2004.
DOI : 10.1021/jo035147y

H. M. Abers, L. J. Hendrickx, R. J. Van-tol, J. Hausmann, A. Perrakis et al., Structure-Based Design of Novel Boronic Acid-Based Inhibitors of Autotaxin, Journal of Medicinal Chemistry, vol.54, issue.13, pp.4619-4626, 2011.
DOI : 10.1021/jm200310q

M. Sun and Z. Bo, Tuning the optical properties of hyperbranched polymers through the modification of the end groups, Journal of Polymer Science Part A: Polymer Chemistry, vol.33, issue.1, pp.111-124, 2006.
DOI : 10.1002/0470845821