Quasi‐perfect polar alignment of nonlinear chromophores in a crystalline H‐bonded guest–host structure: 2‐Amino‐5‐nitropyridinium‐L‐monohydrogentartrate

The nonlinear optical properties of organo‐mineral salts based on 2‐amino‐5‐nitropyridine (2A5NP) and tartrate anions are presented. The mineral anion provides improved structural cohesion compared to van der Waals or hydrogen‐bonded organic molecular crystals while the organic species is responsible for the nonlinear optical activity. 2A5NP is known to exhibit high molecular hyperpolarizability and blue‐shifted absorption relative to p‐nitro‐ aniline‐like molecules.