Raman and infrared spectroscopies are used as local probes to study the dynamics of the Nd-O bonds in the weakly multiferroic NdMn2O5 system. The temperature dependence of selected Raman excitations reveals the splitting of the Nd-O bonds in NdMn2O5. The Nd 3+ ion crystal field (CF) excitations in NdMn2O5 single crystals are studied by infrared transmission as a function of temperature, in the 1800-8000 cm -1 range, and under an applied magnetic field up to 11 T. The frequencies of all 4 Ij crystal-field levels of Nd 3+ are determined. We find that the degeneracy of the ground-state Kramers doublet is lifted (∆0 ~7.5 cm -1 ) due to the Nd 3+ -Mn 3+ interaction in the ferroelectric phase, below TC ~ 28 K.The Nd 3+ magnetic moment mNd(T) and its contribution to the magnetic susceptibility and the specific heat are evaluated from ∆0(T) indicating that the Nd 3+ ions are involved in the magnetic and the ferroelectric ordering observed below ~ 28 K. The Zeeman splitting of the excited crystal field levels of the Nd 3+ ions at low temperature is also analyzed. dependent on the size of the rare-earth [2, 12-15]. The RMn2O5 compounds with large ionic radii (R= La and Pr) do not exhibit a detectable electric polarization and are considered as paraelectrics [14], while those with small ionic radii (R=Sm to Lu) display a finite electric polarization [13]. The intermediate size member of this family NdMn2O5 represents a particular case between the non-ferroelectric PrMn2O5 and the ferroelectric SmMn2O5. Recently, Chattopadhyay et al. [16-17] have revealed the weak ferroelectric character of this compound. The electric polarisation of NdMn2O5 (~2.4 μCm −2 ) is two orders of magnitude smaller than that of other multiferroic members of this series. Moreover, unlike the other multiferroic members of this family, its electrical polarization arises in an incommensurate magnetic state [13]. The RMn2O5 compounds crystallize in the orthorhombic structure [18-19] where edge-shared Mn 4+ O6 octahedra are connected along the c-axis and pairs of Mn 3+ O5 pyramids are linked to two Mn 4+ O6 chains. The rare earth ions are located in distorted RO8 polyhedra. However, there is no consensus on their space group symmetry. Indeed, a slight deviation from the Pbam space group has been recently observed in some compounds of this family [20]. The magnetic frustration of these systems is imposed by the geometric configuration. The loop of five adjacent Mn 3+ and Mn 4+ ions leads to a complex magnetic configuration in the RMn2O5 systems [1, 21-22]. The Mn 3+ and Mn 4+ moments are coupled antiferromagnetically by the exchange parameters J4 along the a-axis and J3 along the baxis [22]. The Mn 3+ moments, in two linked pyramids, couple antiferromagnetically via the exchange parameters J5. As a result of these numerous exchange parameters and the magnetic frustration, RMn2O5 multiferroics with small R ions show multiple phase transitions as a function of temperature. A magnetic transition to an antiferromagnetic order