Cytokinin　(CK)　is　a　type　of　hormone　that　exists　widely　in　plants　and　plays　a　significant　role　in　promoting　cell　proliferation　and　division.　Developing　a　rapid　and　sensitive　method　for　the　detection　of　trace　CKs　remains　challenging.　Microporous　organic　networks　(MONs)　are　novel　materials　widely　used　in　sample　preparation　owing　to　their　excellent　extraction　performance.　Therefore,　a　dispersive　solid　phase　extraction　method　based　on　carboxylated　microporous　organic　networks　(MON-2COOH),　combined　with　ultra-high　performance　liquid　chromatography-tandem　mass　spectrometry　(UPLC-MS/MS)　for　the　detection　of　four　CKs　was　developed.　Upon　introducing　a　carboxyl　group　into　pure　MON,　the　MON-2COOH　material　had　excellent　stability,　high　porosity,　and　a　good　dispersion　effect,　and　provided　more　interaction　sites　to　achieve　good　adsorption　of　target　compounds.　Under　the　best　conditions,　the　established　dSPE-UPLC-MS/MS　method　had　the　advantages　of　low　adsorbent　dosage　(2　mg),　low　detection　limit　(1.0-10.0　pg　mL-1)　and　good　reproducibility　(RSD　＜=　6.54%,　n　=　5).　Synergistic　extraction　mechanisms　involving　pi-pi,　hydrogen　bonding　and　hydrophobic　interactions　were　elucidated　using　both　density　functional　theory　calculations　and　experimental　data.　This　work　also　confirmed　the　feasibility　of　functionalized　MONs　as　satisfactory　adsorbents　for　the　enrichment　of　small　organic　compounds.