Using 1,2,4-triazole and adipic acid as coligands, a novel three-dimensional metal–organic framework, namely {[Cd 4 Cl(trz) 5 (adi)]·H 2 O} n (1) (trz = 1,2,4-triazole, adi = adipic acid) was hydrothermally synthesized and characterized. The crystal structure reveals that three independent Cd(II) centers are linked via one μ 3 -Cl and two μ 3 -COO − groups to form a unique [Cd 4 Cl(CO 2 ) 2 ] tetranuclear cluster, which acts as a 10-connected node joining adjacent four tetranuclear subunits and six 3-connected trz nodes to give a novel (3,10)-connected topological net with the Schläfli symbol (4 3 )(4 18 6 25 6 2 ).