The polarized single crystal absorption spectra of Cs2U(Np)O2Cl4 and CsU(Np)O2(NO3)3 have been measured between 600 and 22 000 cm-1. In the former material five f-f transitions associated with the NpO2 2+ ion have been identified and in the latter material four such transitions. Zeeman effect measurements and MCD spectra are also reported. A perturbation method is used to assign parameters characterizing the f orbital energies, the spin-orbit interaction and the equatorial ligand field. This model is tested against the energies, transition intensities and magnetic properties associated with the observed spectroscopic states.