Thiophene-Based Molecular Materials for Nonlinear Optics

In this paper, we describe the synthesis of a thiophene-based donor- $\pi$ -acceptor system, namely (E)-2-(4-nitrostyryl)-5-phenylthiophene (Th-CN 2 ), which was prepared under basic conditions as previously described in the literature. This thiophene based $\pi$ -conjugated system was mixed with poly(methyl methacrylate) (PMMA) and the resulting thin film was subjected to nonlinear optical investigations by means of both second and third harmonic generation. The obtained nonlinear optical responses have been compared with the previously prepared $\pi$ -conjugated systems as well as with a silica and quartz reference compounds. Although the obtained nonlinear optical response is low, such thiophene-based $\pi$ -conjugated systems are valuable materials for photonic applications.