The　hydrophobic　nature　of　an　extractant　is　particularly　critical　in　the　treatment　of　wastewater.　Considering　that　dicationic　ionic　liquids　(DILs)　are　likely　to　be　more　hydrophobic,　a　comparative　study　of　the　separation　of　phenol　from　waters　using　[NTf2]-　based　monocationic　ionic　liquids　(MILs)　and　DILs　is　carried　out　both　from　experimental　and　theoretical　analysis　perspectives.　Experimental　results　revealed　that　DILs　exhibited　superior　extraction　ability　compared　to　MILs,　with　extraction　efficiencies　of　93.7%　and　97.4%　using　[BMIM][NTf2]　and　[C6(MIM)2][NTf2]2　as　extractants,　respectively.　The　microscopic　examination　through　theoretical　calculations　elucidated　the　higher　hydrophobicity　and　extraction　efficiency　of　DILs　over　MILs.　The　results　indicated　that　the　DIL　showed　stronger　hydrophobicity　than　the　MIL　because　the　hydrogen　bond　strength　between　the　DIL　and　water　was　lower　than　that　of　the　MIL.　Although　the　hydrogen　bond　strength　between　the　DIL　and　phenol　was　lower　than　that　of　the　MIL,　the　stronger　van　der　Waals　forces　existed　between　DIL　and　phenol,　so　DIL　was　more　efficient　in　extracting　phenol.　In　addition,　the　experimental　parameters　were　optimized　to　provide　basic　data　for　application,　such　as　mass　ratio　of　ILs　to　water,　extraction　time　and　temperature,　pH,　and　initial　phenol　content.　Finally,　the　DILs　were　recovered　using　rotary　evaporation　apparatus,　and　the　results　demonstrated　that　DILs　had　good　recovery　and　reuse　performance.　In　brief,　this　work　could　provide　an　effective　method　for　the　treatment　of　phenol-containing　wastewater.　And　the　revelation　of　molecular　mechanism　is　expected　to　positively　impact　the　design　of　high-performance　task-specific　ILs.