Metal　organic　frameworks　(MOFs)　has　been　widely　investigated　as　co-catalysts　for　photocatalysis　owing　to　their　unique　property　for　controlling　the　reaction　kinetics.　They　are　generally　presented　in　a　solid　state.　Recent　studies　have　presented　MOF　in　the　liquid　phase,　meanwhile　preserving　the　framework　structure.　Acting　as　a　co-catalyst,　significantly　improved　efficiency　has　been　realized　for　photocatalytic　CO2　reduction.　This　concept　article　focuses　on　the　chemical　principle　of　liquid　MOF　(LMOF).　Their　applications　in　photocatalysis　and　CO2　adsorption　have　been　discussed　with　showing　key　examples.　In　addition,　the　other　relevant　applications　of　LMOF　have　been　presented.　©　2023　Wiley-VCH　Verlag　GmbH.