A rare chiral 3D cluster-organic framework {[Zn17O5(NTB)6(NDB)3]·41H2O}n () (H3NTB = 4,4',4''-nitrilotrisbenzoic acid and H2NDB = 4,4'-nitrilodibenzoic acid) was prepared and structurally characterized. Complex contains two types of [Zn4(μ4-O)(COO)6] and unreported [Zn9(μ3-O)3(COO)12] SBUs, which link bi- and tri-carboxylic acids and extend to an unprecedented (3,6,12)-connected framework. In addition, electronic structure calculations were performed to scrutinize the features of embedded clusters.