A 3D spin canted cupric MOF is constructed from the layered [Cu 2 Cl(tta) 2 ] n n− and chain-like [Cu(Itta)(I 0.25 tta) 2 ] n 2n− motifs linked by 5-Iodo-1- H -tetrazole from in situ C-H iodination of 1- H -tetrazole. • A novel 5- I -tetrazole based MOF has been prepared by the hydrothermal treatment of CuCl 2 , 1- H -tetrazole and HI acid. • The 5- I -tetrazole can be generated from the Direct C H in situ Iodination of 1- H -tetrazole. • The MOF exhibits spin canted antiferromagnetic couplings. Hydrothermal treatment of cupric chloride and tetrazole in the presence of hydroiodic acid generated a spin canted coordination polymer [Cu 3 (tta) 2 (Itta)(I 0.25 -tta) 2 Cl] (1), (Htta = 1- H -tetrazole, Itta = 5-Iodo-1- H -tetrazole), showing a 3D network constructed from layered [Cu 2 Cl(tta) 2 ] n n– and chain-like [Cu(Itta)(I 0.25 tta) 2 ] n 2n– moieties linked through expensive Itta groups in situ C H iodinated from cheap Htta. [ABSTRACT FROM AUTHOR]