In this contribution, a new method for the fabrication of complex polymeric microfluidic devices is presented. The technology has three distinct features : (i) liquid photoresists in contact with the phomask, (ii) readily removed sacrificial materials, and (iii) living radical processes, enable multiple polymeric chemistries and mechanical properties while simultaneously enabling facile fabrication of 3D geometries and surface chemistry control. This contribution details Contact Liquid Photolithographic Polymerization (CLiPP) fabrication techniques that are utilized for the fabrication of a geometrically complex brain slice perfusion device, which has several distinct and unique features such as (i) facile connections to auxiliary equipment, (ii) large unobstructed areas that allow access for a variety of detection equipment, e.g. conventional glass-pulled microelectrode even in restricted areas below microscopes, (iii) unique perfusion structures for optimized nutrient and waste transport and (iv) separated perfusion and drug fluid streams.