Naphthalene as a fuel additive to ethanol was examined in a swirl combustor with the objective to obtain efficient burning and ultra-low emissions using different heating value fuels. Naphthalene is a polyaromatic compound often regarded as a waste fuel that results in high levels of pollutants emission. The effectiveness of naphthalene as a fuel additive to ethanol on NO and CO emissions and stability was determined. The naphthalene concentration was varied from 0 to 0.4 mol/L in ethanol, corresponding to a heating value increase of 8.8% on a volumetric basis (or 5.7% on mass basis). Emissions data were reported for Colorless Distributed Combustion (CDC) using N-2/CO2 dilution, at equivalence ratios (Phi) of 0.9 and 0.7. The data under normal fuel-air combustion conditions also reported, clearly showing the benefits of CDC. NO and CO emission below 1 and 6 ppm, respectively, were achieved under CDC conditions for each of the naphthalene-ethanol fuels examined. The results at both the equivalence ratios showed lower NO emission with increase in naphthalene concentration, which provided higher heating value fuel mixture. The CO emission was also low and remained negligibly unchanged with change in naphthalene concentration and equivalence ratio. The results show the use of naphthalene addition to ethanol for increased heating value fuel with ultra-low emissions and higher stability under distributed combustion conditions.