A new synthetic route has been utilized for the formation of multiple-shaped Pt nanoparticles (NPs) under UV-photoirradiation. The one-step process exclusively generates different shapes, such as spheres, cubes, short and long wires, and flakelike nanostructures. The reduction of PLO V) ions was clone using alkaline 2,7-DHN in CTAB micellar media under 3 h UV-photoirradiation. The synthesized Pt NPs are stable for more than 4 months in ambient conditions. By changing the surfactant-to-metal on molar ratios and the concentration of reducing agent, the particle size and shape can be tuned. The mechanisms of the particles formation with variable shapes and the effects of different reaction parameters are studied in detail. The present approach can be extended to a fast synthetic method for the formation of other metallic and semiconductor particles with variable shapes. The evolved Pt NPs will find promising applications in different types of organic and inorganic catalysis reactions, medicinal applications, and nanoelectronics.