Petrochemical　refineries　must　separate　hydrocarbon　mixtures　on　a　large　scale　for　the　production　of　fuels　and　chemicals.　Typically,　these　hydrocarbons　are　separated　by　distillation,　which　is　extremely　energy　intensive.　This　high　energy　cost　can　be　mitigated　by　developing　materials　that　can　enable　efficient　adsorptive　separation.　In　this　critical　review,　the　principles　of　adsorptive　separation　are　outlined,　and　then　the　case　for　C-4　separations　by　using　zeolites　and　metal-organic　frameworks　(MOFs)　is　examined.　By　analyzing　both　experimental　and　theoretical　studies,　the　challenges　and　opportunities　in　C-4　separation　are　outlined,　with　a　focus　on　the　separation　mechanisms　and　structure-selectivity　correlations.　Zeolites　are　commonly　used　as　adsorbents　and,　in　some　cases,　can　separate　C-4　mixtures　well.　The　pore　sizes　of　eight-membered-ring　zeolites,　for　example,　are　in　the　order　of　the　kinetic　diameters　of　C-4　isomers.　Although　zeolites　have　the　advantage　of　a　rigid　and　highly　stable　structure,　this　is　often　difficult　to　functionalize.　MOFs　are　attractive　candidates　for　hydrocarbon　separation　because　their　pores　can　be　tailored　to　optimize　the　adsorbate-adsorbent　interactions.　MOF-5　and　ZIF-7　show　promising　results　in　separating　all　C-4　isomers,　but　breakthrough　experiments　under　industrial　conditions　are　needed　to　confirm　these　results.　Moreover,　the　flexibility　of　the　MOF　structures　could　hamper　their　application　under　industrial　conditions.　Adsorptive　separation　is　a　promising　viable　alternative　and　it　is　likely　to　play　an　increasingly　important　role　in　tomorrow＇s　refineries.