This study investigates the effects that manganese(IV) dioxide particles have on 2,3-naphthalenediol at varying pH levels (i.e., initial pH of 4.58, 5.85, and 8.75) and under different organic concentration conditions (4×10−3, 4×10−4, and 4×10−5 M), and assesses the importance of Mn oxides on abiotic catalysis of the multiple-ringed aromatic compound. Proton concentration affected the rates of reductive dissolution; as the pH values increased, the rate of reductive dissolution decreased, as predicted by theory. Also, as the concentration of naphthalenediol increased, the rate of reductive dissolution increased, although not proportionally; thus indicating that a majority of the active sites had been occupied. In addition, the results tend to confirm that electron transfer/organic release from the oxide surface is the rate-limiting step. This study demonstrates that in an oxic environment and in the presence of 2,3-naphthalenediol, MnO2 particles undergo reductive dissolution; in the process, naphthalenediol is oxidized. An oxidation by-product of reductive dissolution is an insoluble polymerized organic. The organic by-product was deep-brown in appearance, very similar to that of "humified" material. Using infrared spectroscopy, energy-dispersive x-ray analysis, and a microelemental analysis, the "humified" products appeared to be comprised mainly of constituents originating from naphthalenediol.