Elaborate control of wettability in a single platform is essential for materials' applications towards oil-water separation, but it still remains challenging. Herein, we performed postcoordination modification of Mg2(dobpdc) with monoamines of various alkyl chain lengths, enabling both long-term hydrolytic stability and facile fine-tuning of wettability. An efficient separation of oil-water mixtures was achieved by using the octylamine-appended framework (OctA). We also prepared an OctA/reduced graphene oxide aerogel that showed exceptional absorption capacities towards organic solvents and oil as well as superb recyclability with maintained absorbency.