A simple, easily visualized thin-layer chromatography (TLC) staining experiment is presented that highlights the difference in reactivity between aromatic double bonds and nonaromatic double bonds. Although the stability of aromatic systems is a major theme in organic chemistry, the concept is rarely reinforced "visually" in the undergraduate curriculum. With the use of a TLC plate to immobilize a range of unsaturated hydrocarbons, their UV fluorescence properties and their susceptibility to oxidation, using a permanganate stain, can be easily and rapidly visualized in a classroom setting. (Contains 1 table and 2 figures.)