A series of melanin derivatives has been prepared by functionalization with dendritic azobenzene molecules under basic conditions with (K 2CO3) 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. © 2014 the Partner Organisations.