Synthesis, magnetism and quantum Monte Carlo studies of two Cu(II)-based ferromagnetic coordination polymers

► Two Cu(II) based coordination polymers of H2CMBA ligand were obtained. ► Magnetic measure exhibits that they feature ferromagnetic properties. ► Quantum Monte Carlo studies reveal the coupling parameters of two Cu(II) ions. ► 4, 4′-bpy ligand exhibits weak antiferromagnetic interaction with − 0.36 cm− 1.