Polyaniline (PANI) was prepared in the presence of the acidic dye scarlet 3R. Color tuning was performed on PANI through doping–dedoping processes and by changing the solvent used during the optical absorption spectroscopic measurements. The chemical structure of the resulting polymer–dye composite was analyzed using infrared absorption spectroscopy, and it showed the occurrence of secondary doping in m-cresol. The shape of the UV–Vis optical absorption spectra for the composite solution is

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... ndent on the types of organic solvents used during the analysis, which was influenced by the conformation of PANI and the ionic interactions between PANI and scarlet 3R.