A novel lacmoid-based deep eutectic solvent was prepared by mixing of choline chloride as hydrogen bond acceptor and lacmoid as hydrogen bond donor. The mixture of both components was heated until a stable purplish blue homogenous liquid DES dye was formed at 25 °C temperature. The physical and chemical properties of the DES dye ink were studied at 25 °C temperature and characterized by FT-IR, TLC, TGA, 1H-NMR and DSC techniques. The DES dye ink was applied as writing ink and it revealed interesting characteristics for writing without feathering, fading, and penetrating the reverse side of paper and drying by adsorption within few seconds. Moreover, The DES dye ink showed high stability in water for 72 h due to the absorption of DES dye ink by cellulose paper. The green DES dye ink exhibited an effective ability to replacement of pigments and organic compounds used in making writing ink.
