Some novel 5,8-diaryl-5,7,8,9-tetrahydropyrimido[5,4-e]tetrazolo[1,5-a]pyrimidin-6(4H)-one derivatives are prepared via one-pot reaction of aromatic aldehydes, 2-aminotetrazole and cyanoacetamide using two different types of catalytic systems including nano-magnetic catalyst supported with functionalized 4-amino-pyridine silica (MNPs@SiO2-Pr-AP) and NEt3.The highlighting points of using MNPs@SiO2-Pr-AP are easy purification, reusability of the catalyst, good yields of products with short time reactions compared with NEt3. Also the DFT calculations showed that a trans-like isomer is more stable than other possible isomers/conformers. The experimental data are also consistent with a pure compound rather than a mixture of isomers.