A high quality eumelanin thin film featuring efficient reversibility of the water induced conductivity switch and high biocompatibility was obtained,viaammonia-induced solid state polymerization of a 5,6-dihydroxyindole thin film.

N-functionalization of 5,6-dihydroxyindole with a hydrophilic triethyleneglycol (TEG) chain provides access to a\ud new class of water-soluble eumelanin-like materials with relatively high dielectric constant and polyelectrolyte\ud behaviour, reflecting enhanced charge transport by in-depth incorporation of hydration networks

The oxidative polymerization of 5,6‐dihydroxyindoles and related hydroxyindoles at pH<3 is diverted from the usual eumelanin‐forming pathway to produce mixtures of symmetric and asymmetric triazatruxenes (TATs), which could be separated and characterized for their opto‐electronic properties with the aid of TD‐DFT calculations. Data showed that the asymmetric isomers exhibit higher fluorescence quantum efficiencies, lower HOMO–LUMO gaps, better film homogeneity, and a more definite aggregation behavior than the symmetric counterparts, suggesting promising applications in organic electronics. The enhanced luminance exhibited by the OLED devices fabricated with blends of the synthesized TATs in poly‐9‐vinylcarbazole confirmed the potential of the asymmetric skeleton as new versatile platform for light‐emitting materials.