Optical properties of new 5-(4-phenylethynyl)-substituted-1,10-phenanthroline derivatives

► Synthesis and optical properties of new 5-substituted-1,10-phenanthroline derivatives. ► Sonogashira reaction was used for the substitution. ► Structure-polarisability relationship analyzed according to Lippert-Mataga correlation. ► Theoretical study was carried out with DFT calculations. ► Fine-tuning of the internal charge-transfers within nonlinear compounds.