Bulk samples, layers, quantum well, and quantum dot structures of II-Mn-VI samples all show coexistence of slow and fast components of Mn²⁺ photoluminescence decay. Thus, fast photoluminescence decay cannot be related to low dimensionality of a host material. This also means that the model of the so-called quantum confined atom is incorrect. Based on the results of time-resolved photoluminescence and optically detected magnetic resonance investigations we relate the observed lifetime decrease in Mn²⁺ intra-shell transition to spin dependent magnetic interactions between localized spins of Mn²⁺ ions and between Mn²⁺ ions and spins/magnetic moments of free carriers. The latter mechanism is enhanced in nanostructures.