Push-pull molecules with a systematically extended π-conjugated system featuring 4,5-dicyanoimidazole

Eighteen chromophores featuring 4,5-dicyanoimidazole as an acceptor moiety, a systematically enlarged π-conjugated spacer and methoxy and N,N-dimethylamino groups as donors were synthesised and characterised by X-ray analysis, electrochemistry, UV–Vis and fluorescence spectroscopy whilst NLO properties were calculated. Quantitative relationships between measured properties and structural features of the chromophores were also evaluated.