Cluster-based　metal-organic　frameworks　(MOFs)　supported　by　mixed　ligands　usually　have　unique　properties　due　to　the　combined　features　from　different　ligands.　In　this　regard,　it　is　rather　rare　for　carboxylate　and　pyrazolate　ligands　as　＂struts＂　to　be　present　in　one　MOF.　Herein,　four　isostructural　heptanuclear　Co(II)-based　MOFs　based　on　mixed　carboxylate　and　pyrazolate　ligands,　[Co-7(mu(3)-OH)(4)(BDP)(2)(IPA-X)(5)]　(BUT-127-X;　X　=　H,　OH,　Br,　and　NH2,　respectively;　BDP2-　=　1,4-benzenedipyrozolate　and　IPA(2)(-)　=　isophthalate),　were　synthesized　through　carefully　tuning　the　solvothermal　reaction　conditions.　Structurally,　in　these　MOFs,　alternately　connecting　Co-7(mu(3)-OH)(4)　clusters　with　carboxylate　ligands　(IPA(2-)-X)　generate　two-dimensional　(2D)　layers,　which　are　further　supported　by　the　pyrazolate　ligands　(BDP2),　giving　rise　to　the　final　pillared-layer　frameworks　with　well　adjustable　pore　surface　environments.　They　have　permanent　porosity　with　high　Brunauer-Emmett-Teller　surfaces　from　1030　to　1314　m(2)　g(-1)　as　well　as　good　chemical　stability.　Interestingly,　four　Co(II)　atoms　in　the　Co-7(mu(3)-OH)(4)　cluster　exhibit　a　five-coordinated　configuration　that　affords　open　metal　sites.　The　feature　allows　these　MOFs　to　present　good　CO2　adsorption　performance　and　catalytic　activity　for　the　CO2　fixation,　where　BUT-127-NH2　gave　the　best　catalytic　performance　for　the　cycloaddition　of　CO2　with　epoxides　into　cyclic　carbonates　under　mild　conditions　(1　bar,　25　and　50　degrees　C).