Ku dhasho Vernon, Dembélé wuxuu xirfaddiisa ka bilaabay Rennes ka hor inta uusan ku biirin Dortmund 2016. Wuxuu ku guuleystay DFB-Pokal isagoo la ciyaaraya "die Borussen" xilli ciyaareedkii 2016-17, isagoo dhaliyay gool
waa la soo gabagabeeyay. Sannad ka dib, wuxuu u wareegay Barcelona lacag bilow ah oo dhan € 105 milyan, isagoo noqday waqtigaas ciyaaryahanka labaad ee ugu qaalisan abid oo ay weheliyaan muwaadinkiisa Paul Pogba. Dembélé ayaa markii dambe ku guuleystay La Liga iyo Copa del Rey labadaba xilli ciyaareedkii ugu horreeyay ee dhaawac ku dhacay Spain.