4,5-Dihydroxy-2-nitrobenzaldehyde is used as a reagent in the synthesis of 5,6-diacetoxyindole which is a stable eumelanin precursor. 4,5-Dihydroxy-2-nitrobenzaldehyde is also used in the preparation of 6-aminoisoproterenol which is an impurity of the non-selective beta-adrenergic agonist, Isoproterenol (I874200, HCl).