Microtrenches have been produced on the surface of a glass substrate using conven- tional photolithography technique. When subsequently deposited on the micro-patterned substrate, discotic triphenylene molecules are found to assemble into columns with ori- entational ordering. Homogeneous alignment of the discotic columns has been produced on the substrate with parallel microtrenches. The orientational direction of the discotic columns can be controlled using a set of controlling microtrenches. By properly mod- ifying the topological structures of the controlling microtrenches we are able to tune the discotic columns assembled in the primary trenches to align either parellel or perpendicular to the walls of the trenches.