In this seminar, we aim to present the results of two recent works centred at the use of spectropolarimetric data obtained with the CRISP instrument at the SST in the Ca II 845.2 nm line. With these observations, we obtain information about the magnetic field present in chromospheric spicules and coronal rain clumps. For this purpose, we have used the Weak-field approximation (WFA), which albeit being computationally simple to implement, needs careful assessment of the conditions of the plasma to be correctly applied. Magnetic fields of the order of hundreds of Gauss are inferred. We also combine the Ca II 845.2 nm observations with simultaneous Hα observations to estimate the temperature and non-thermal velocity of the plasma in coronal rain and spicules using the observed Doppler amplitude.