Abstarct: The green application of nitrogen-rich mextal-organic frxameworks (N-rich MOF) and their magnetic composites in aza-Michael reaction as a catalyst and selective adsorption of cationic dye (methylene blue) in aqueous solution was investigated. The synthesis method of two types of N-rich anionic MOF ([ZnBT(H2O)2]n(ZnBT), [CuBT(H2O)2]n(CuBT)) from 5,′5-bistetrazole ligand (H2BT) to increase efficiency and the reduction of energy consumption was optimized by hydrothermal method within 24 hours with the ratio (ligand 3: mextal salt 3: solvent 1). To increase the applicability and ease of separation, magnetite nanoparticles encapsulated in polyvinylpyrrolidone (Fe3O4@PVP) were stabilized on the surface of N-rich MOFs (Fe3O4@PVP@ZnBT, Fe3O4@PVP@CuBT) by ultrasonic waves and hydrothermal method. Different analysis such as FT-IR, 1HNMR, 13CNMR, XRD, TEM, SEM, EDX & mapping, BET-BJH, Zeta, DLS, VSM and ICP were used to identify the synthesized materials. The catalytic properties and adsorption selectivity of MOFs and their anionic magnetic composites were investigated in the aza-Michael reaction with different amines and in the removal of cationic and anionic dyes. Fe3O4@PVP@CuBT (3% W) as a strong and recyclable Lewis acid catalyst under mild conditions showed the highest conversion percentage (94%) in the reaction of 2-vinylpyridine with aniline. ZnBT showed the highest adsorption percentage of methylene blue (20mg/L) in aqueous solution compared to other adsorbents (98.27%) in a period of 10 minutes.The characteristic of selectivity in ZnBT with amounts (0.003, 0.005, 0.007, 0.009g) of the selected adsorbent in two cationic dyes (methylene blue (MB), rhodamine B (RhB)) and anionic dye (methyl orange (MO)) with a concentration of (20m/L) during 12 minutes (R.T, normal pH) was investigated. The removal of MB, MO and RhB was 98%, 4% and 2%, respectively. ZnBT showed a high adsorption capacity of MB (458mg/g) compared to larger cationic dye (RhB) and anionic dye (MO). The kinetics and isotherm data of MB removal by anionic MOF follow pseudo-second-order kinetics (R2=0.999) and Langmuir isotherm (R2=0.861).