Physical　and　chemical　technologies　have　been　continuously　progressing　advances　in　neuroscience　research.The　development　of　research　tools　for　closed-loop　control　and　monitoring　neural　activities　in　behaving　animals　is　highly　desirable.In　this　paper,we　introduce　a　wirelessly　operated,miniaturized　microprobe　system　for　optical　interrogation　and　neurochemical　sensing　in　the　deep　brain.Via　epitaxial　liftoff　and　transfer　printing,microscale　light-emitting　diodes　(micro-LEDs)　as　light　sources　and　poly(3,4-ethylenedioxythiophene)　polystyrene　sulfonate　(PEDOT:PSS)-coated　diamond　films　as　electrochemical　sensors　are　vertically　assembled　to　form　implantable　optoelectrochemical　probes　for　real-time　optogenetic　stimulation　and　dopamine　detection　capabilities.A　customized,lightweight　circuit　module　is　employed　for　untethered,remote　signal　control,and　data　acquisition.After　the　probe　is　injected　into　the　ventral　tegmental　area　(VTA)　of　freely　behaving　mice,in　vivo　experiments　clearly　demonstrate　the　utilities　of　the　multifunctional　optoelectrochemical　microprobe　system　for　optogenetic　interference　of　place　preferences　and　detection　of　dopamine　release.The　presented　options　for　material　and　device　integrations　provide　a　practical　route　to　simultaneous　optical　control　and　electrochemical　sensing　of　complex　nervous　systems.