Final state phases in B → Dπ, ¯ Dπ decays are calculated. The CP-violating asymmetry A (t) is shown to be independent of strong phases due to their cancellation. An estimate of A (t) is given so as to determine sin (2β + γ). Time dependent B-decays are a good source of our knowledge regarding CP-violation (For a review see for example refrences [1] and [2]). In particular it is convienent to wr...