A novel tubular microreactor to intensify mixing, namely arc flow inverter (AFI) was proposed and the mixing behavior was investigated. The design concept of AFI expanded a design space of mixing/reactor devices consisting of curved tubes and 90 degrees bends compared with conventional coiled flow inverter (CFI). The fabrication difficulties were overcome by using 3D printing technology. Numerical study on hydrodynamics NRe ≤ 400 revealed that the profile of Dean vortices was spatially periodic along the axis of AFI. The narrower residence time distribution in AFI compared to CFI implied an enhanced lateral mixing due to the Dean vortices. Micro-mixing time in AFI was experimentally accessed via Dushman-Villermaux reaction. The AFI outperformed other fluidic devices in the literature in terms of the coefficient of mixedness.