INTRODUCTION Janus particles are compartmentalized colloids which possess two sides of different chemistry or polarity. These particles have moved into the focus of various research groups ranging from physics, chemistry to biological science. In general, Janus particles can be divided into several classes according to their architecture and dimensionality (see Scheme 1). Most commonly, spherical Janus particles can be imagined. In addition, two types of Janus cylinders (1D) and two types of disc-like particles (2D) are conceivable. The lack of centrosymmetry is inherent to all of these particles and is the major challenging aspect in their preparation.