The structures of honeycomb-patterned thin polymer films fabricated by casting polystyrene solution under humid conditions were controlled by illumination of ultraviolet (UV) light by the assistance of an added light-sensitive amphiphilic copolymer (A ls ) in the casting solution. A ls was synthesized through the radical copolymerization of ruthenium(4-vinyl-4′-methyl-2,2′-bipyridine)bis(2,2′-bipyridine)bis(hexaflurophosphate) with N-vinylcarbazole. The synthesized A ls was characterized using spectroscopic methods and a thermogravimetric analyzer. An appropriate duration of light illumination in a suitable concentration of A ls minimized the irregularity of the honeycomb pattern. However, irregular patterns were induced by an excessive amount of A ls or by excessive illumination time.