Graphene has recently emerged as an attractive material for neural sensing and stimulation, owing to its flexibility, transparency, excellent electrical conductivity and low noise characteristics. Monolayer graphene and multi-layer porous graphene can be engineered for neural interface applications showing advantages in different aspects. The transparent monolayer graphene electrodes enable simultaneous optical imaging and electrophysiological recordings. We have demonstrated that neural tissue can be imaged through transparent graphene electrodes using multi-photon microscopy without causing any light-induced artifacts in the electrical recordings. Combining optical imaging with electrophysiological recordings enables studies of neural activity with high spatial and temporal resolution simultaneously. Furthermore, graphene electrodes exhibit five to six times less noise compared with Au electrodes of the same size in in vivo recordings. In order to increase the surface area and charge injection capability, porous graphene have been utilized to fabricate neural stimulation electrodes. The 3D structure benefits from graphene’s good conductivity and generates greatly increased capacitance compared to the planar graphene and traditionally used bulk metals. Electrochemical tests were performed on electrodes with various areas. Impedance of the porous electrodes show two orders of magnitude decrease compared to Au electrodes of comparable size. Cyclic voltammetry and pulsed voltammetry results show enhanced charge storage and charge injection capacity for the porous electrodes. 16-electrode and 64-electrode arrays fabricated using standard micro fabrication processes have been used in in vivo neural recording and stimulation experiments. We have demonstrated recordings of evoked potentials from rat somatosensory cortex with high SNR using porous graphene electrodes. Moreover, we have used same arrays for cortical stimulation from the motor cortex of rat to evoke transient ankle and knee flexion in the contralateral leg. In summary, two forms of graphene, namely the monolayer graphene and porous graphene, were engineered for different neural applications. The monolayer graphene electrode shows the capability to record brain activity while simultaneously resolving individual cells and their connections through optical imaging. The porous graphene electrode greatly increases the charge-injection capacity for neural stimulation applications.