This work presents a novel planar memimpedance device, named AMemImp, that consists of a Silver/reduced Graphene Oxide/Silver junction. AMemImp exhibits a unique ability for analog memimpedance tuning. For the first time in the literature, it is shown that the resistance and the capacitance of AMemImp device can be tuned simultaneously using a suitable voltage pulse. The oxide gap size (the distance between the metal electrodes) effect on both resistance and capacitance is also studied. It is proved that AMemImp capacitance follows semiconductors-based capacitance behavior during full ON state, while it has the insulator-based parallel plate capacitance characteristics during full OFF state. As a demonstrator, the analog capacitance switching behavior of AMemImp is utilized to build 2 capacitors and 2 transistors (2C2T) computation cell to perform multiply-and-accumulate operation. The non-volatile memcapacitor is exploited to store the data during the programming mode and perform multiplication in the computation mode. The 2C2T is used in a 5x4 crossbar where 20 operations are achieved in a single clock cycle with an error of 5.7%. AMemImp is considered great merit for tunable memory, computing, and RF systems.