Intramolecular charge transfer, solvatochromism and hyperpolarizability of compounds bearing ethenylene or ethynylene bridges

► The solvatochromism of six ethenyl and four ethynyl push-pull compounds was investigated. ► The ground (μg) and excited state (μe) dipole moments were calculated. ► The μe(ICT) of the solvent-stabilized state formed by the ICT process were obtained. ► The quadratic hyperpolarizability, βCT, was then derived. ► These photostable compounds can offer potential interest for their NLO responses.