The main aim of this proposal is to investigate the magnetic structures of compounds [CH3NH3][M(HCOO)3] with M = Ni2+(1) and Cu2+(2). Low temperature magnetic data, collected in zero-field-cooling (ZFC) and field-cooling (FC) conditions at different applied magnetic fields, show that the Ni compound exhibits an antiferromagnetic behaviour with a spin-canting below 34 K and the Cu-based sample below 4 K with a weak spin canting. Previous experiments with neutron powder diffraction showed that the weak magnetic signal in compounds 1 and 2 is masked due to the large incoherent contribution of the hydrogen atoms present in the proposed compounds, thus single crystal experiment are necessary in order to analyse their magnetic structures.In the present experiment we intend to collect full data acquisitions at two different temperatures corresponding to the paramagnetic phase (50K for 1 and 20K for 2), and to the magnetic ordered phase below the TN (at 2K), to determine the magnetic structure of the compounds. In order to perform this task, we apply for 14 days of beam-time on D19 instrument using the helium-based displex operated at 1.45 Å.