  The first observation of the color-suppressed decay mode \bar{B}^0_d -->
D^(*)0 \pi^0 by the Belle and CLEO Collaborations makes a quantitative analysis
of the isospin relations for the amplitudes of B --> D^(*)\pi possible. The
strong (isospin) phase difference in B --> D\pi transitions is found to be
about 29^\circ by use the Belle data or 26^\circ by use of the CLEO data,
implying that final-state interactions might not be negligible. Applying the
factorization approximation to I=3/2 and I=1/2 isospin amplitudes of B --> D\pi
decays, we obtain the ratio of the effective Wilson coefficients a^{eff}_1 and
a^{eff}_2: a^{eff}_2/a^{eff}_1 \approx 0.27. A similar analysis shows that the
magnitude of final-state interactions in B --> D^*\pi might be comparable with
that in B --> D\pi, and the factorization hypothesis works consistently in both
of them.
