Here, we investigate a low-cost, liquid exfoliated, graphene-based, flexible, 16 channel μ-ECoG array implanted on the cortex for high-resolution neurophysiological recording and in vivo optical imaging. For the first time, a low-cost, mass-producible, stencil-based fabrication technique is successfully developed where a flexible mask was crafted with a laser cutter that evades the use of expensive micromachining. The array maintained an average surface impedance of ~ 369 MΩ.μm2 at 1 kHz after 1 week of implantation, which is ~ 4 times lower than the prior reports. We also present a direct comparison of the simultaneous recording in awake and anesthetized states.