Photolytic irradiation of 2(-4 thiazolyl) benzimidazole in acidic and neutral medium using benzophenone (methyl orange) as sensitizer .Photochemical reactions depend on the source of the reaction. for example Sunlight, UV light and visible light. 2-(-4 thiazoly) benzimidazole(2gm powder) was dissolved in dried and distilled ethyl alcohol (C2H5OH) 200 ml and add 0.01gm sensitizer. The solution mixture was irradiated in presence of 125w and 250 w mercury vapor lamp for around 40 to50 hrs. The progress of the reaction mixture was observed at regular intervals from Thin layer chromatography method every10 hrs. After 41 and 55 hrs two new spots appeared on the plate of TLC. At the end of the reaction two products were found. This products show many pharmaceutical properties like primarily in treatment to control the stomach warm mold and fungal diseases infection, also widely used in (thiabendezole medicine), anti parasitic medicine for treatment of roundworm, hookworm and helminthes