Conjugated Polycyanines: A New Class of Materials with Large Third‐Order Optical Nonlinearities

A fully conjugated polycyanine (AJMPC02) showing a very large Re(γ) value of −9.0 × 10−57 mks at 1.3 μm is synthesized. It is used as a host polymer for anionic TCF‐cyanines for creating a complementary polymeric cyanine salt complex, which exhibits a Re(γ) value of −5.6 × 10−57 mks at 1.3 μm. A good optical quality thin film based on AJMPC02‐TCF gives a Re(γ) value of −2.1 × 10−18 mks at 1.3 μm and −8.5 × 10−19 mks at 1.55 μm, which are among the highest values reported for molecular materials, and much higher than those derived from silicon.