Pure leptonic radiative decays of heavy-light mesons are calculated using a very simple non-relativistic model. Dominant contribution originates from photon emission from light initial quark. We find $BR(B^pmtoell ugamma)sim3.5times10^{-6}$ and $BR(D_sto ell ugamma)sim1.7 times10^{-4}$. The importance of these reactions to clarify the dynamics of the annihilation graph is emphasized.
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