We give an overview of recent results concerning exciton and carrier tunneling and relaxation in II–VI asymmetric double quantum wells structures with semimagnetic (diluted magnetic) wells or barriers. We undertake the issue of the spin relaxation and injection in the tunneling process and we discuss the dependence of the tunneling efficiency and spin injection on the energy detuning between the initial and final state of the process. The fast tunneling of excitons as whole entities was observed with efficiency strongly dependent on the barrier width, exciton detuning and the relation between detuning and optical phonon energy. In the energy transfer processes an important role of the charged excitons formation is observed. As a result of high sensitivity of energy levels in semimagnetic semiconductor to magnetic field, the thermodynamical redistribution of neutral and charged excitons dependence in magnetic field is observed and must be taken into account in the analysis. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)