  We investigate the decays of pi^0, eta and eta-prime into two photons in an
effective U(3) chiral Lagrangian approach without employing large N_c
arguments. Tree level and one-loop contributions from the anomalous
Wess-Zumino-Witten Lagrangian are calculated and the importance of
eta--eta-prime mixing is discussed. Unitarity corrections beyond one-loop play
an important role for the decays with off-shell photons and are included by
employing a coupled channel Bethe-Salpeter equation which satisfies unitarity
constraints and generates vector-mesons from composed states of two
pseudoscalar mesons.
