The properties of the air/liquid interface of toluene have been examined using second harmonic generation of laser light. By selection of the appropriate input laser polarization and output second harmonic polarization, the molecular plane of toluene was found to be inclined by 42 degrees to the surface normal. The effect of the photochromic fulgide (E)-[alpha-(2,5-dimethyl-3-furyl)ethylidene] (dicyclopropylmethylene)-2,5-furandione dissolved in toluene on the air/toluene interface was also studied. The presence of the fulgide was found to lower the intensity of second harmonic, and upon apparent monolayer formation, its molecular plane was found to be inclined to the surface normal.