Extending our earlier treatments of π 0 , η c and η b , we study the η-η ′ system and its γγ decays using a model which is a leading version of the consistently coupled Schwinger-Dyson (SD) and Bethe-Salpeter (BS) approach. The electromagnetic interactions are incorporated through a (generalized) impulse approximation consistent with this bound-state approach, so that the Ward-Takahashi identities of QED are preserved when quarks are dynamically dressed. To overcome some of the limitations due to the ladder approximation, we introduce a minimal extension to the bound-state approach employed, so that the U A (1) problem is avoided. Pointing out which of our predictions hold in the coupled SD-BS approach in general, and which are the consequences of the specific, chosen model, we present the results for the axial-current decay constants of η 8 , η 0 , and of their physical combinations η and η ′ , the results for the γγ-decay constants of η 0 and η 8 , for the two-photon decay widths of η and η ′ , and for the mixing-independent R-ratio constructed from them.