Hollow particles play an important role in microencapsulation – a process that has been widely exploited for controlled release of drugs. Here we report the fabrication of hollow gold nano-flask particles by a simple templating process. Non-close-packed colloidal monolayers prepared by a spin-coating process are used as templates. A thin film of gold can be sputtered or electrolessly plated on the surface of the particles and the silica templates can be removed later on to form flask-shaped hollow nanoparticles. The resulting particles exhibit tunable plasmonic properties which can be easily tuned by changing the template particle size and the shell thickness. The optical properties of the two-dimensional (2D) ordered hollow particles have also been investigated by both experiments and theoretical calculation using a rigorous coupled-wave analysis (RCWA) model. The interior of the hollow nanoshells can be filled up with chemicals and the opening can then be sealed by a thin layer of hydrogel. We show that the chemicals inside the nanoshells can be delivered in a controlled manner when a laser is illuminated on these composite particles.