Concise Multigram-Scale Synthesis of Push-Pull Tricyanofuran-Based Hemicyanines with Giant Second-Order Nonlinearity: An Alternative for Electro-optic Materials

Highly stable and highly soluble push–pull heptamethine hemicyanines based on the tricyanofuran electron‐accepting group can be prepared on a 15 g scale. The compounds display giant second‐order nonlinear figure of merit, μβ of up to 31 000×10−48 esu, and lead to a poled material with a second‐order nonlinear response, r33 of 90 pm V−1 at 1.06 μm Highly stable and highly soluble push–pull heptamethine hemicyanines based on the tricyanofuran electron‐accepting group (see figure) can be prepared on a 15 g scale. The compounds display giant second‐order nonlinear figure of merit, μβ of up to 31 000×10−48 esu, and lead to a poled material with a second‐order nonlinear response, r33 of 90 pm V−1 at 1.06 μm.