  Based on 2.93 fb$^{-1}$ $e^+e^-$ collision data taken at center-of-mass
energy of 3.773 GeV by the BESIII detector, we report searches for the singly
Cabibbo-suppressed decays $D^{+}\to\omega\pi^{+}$ and $D^{0}\to\omega\pi^{0}$.
A double tag technique is used to measure the absolute branching fractions
$\mathcal{B}(D^{+}\to\omega\pi^{+})=(2.79\pm0.57\pm0.16)\times 10^{-4}$ and
$\mathcal{B}(D^{0}\to\omega\pi^{0})=(1.17\pm0.34\pm0.07)\times 10^{-4}$, with
statistical significances of $5.5\sigma$ and $4.1\sigma$, respectively. We also
present measurements of the absolute branching fractions for the related $\eta
\pi$ decay modes. We find
$\mathcal{B}(D^{+}\to\eta\pi^{+})=(3.07\pm0.22\pm0.13)\times10^{-3}$ and
$\mathcal{B}(D^{0}\to\eta\pi^{0})=(0.65\pm0.09\pm0.04)\times10^{-3}$, which are
consistent with the current world averages. The first and second uncertainties
are statistical and systematic, respectively.
