A series of melanin derivatives has been prepared by functionalization with dendritic azobenzene molecules under basic conditions with (K₂CO₃) and without (Et₃N) a potassium ion. The dendritic melanins treated with K₂CO₃ show excellent solubility in water and tetrahydrofuran. This may be due to the multivalent chelating properties between the heteroatoms of melanin and potassium ions. These highly soluble dendritic melanins were coupled with TiO₂ nanotube arrays easily for enhanced photocurrent generation.