  We investigate the magnetic dipole decays $V\to P\gamma$ of various
heavy-flavored mesons such as $(D,D^*,D_s,D^{*}_s,\eta_c, J/\psi)$ and
$(B,B^*,B_s,B^*_s,\eta_b,\Upsilon)$ using the light-front quark model
constrained by the variational principle for the QCD-motivated effective
Hamiltonian. The momentum dependent form factors $F_{VP}(q^2)$ for $V\to
P\gamma^*$ decays are obtained in the $q^+=0$ frame and then analytically
continued to the timelike region by changing ${\bf q}_\perp$ to $i{\bf
q}_\perp$ in the form factors. The coupling constant $g_{VP\gamma}$ for real
photon case is then obtained in the limit as $q^2\to 0$, i.e.
$g_{VP\gamma}=F_{VP}(q^2=0)$. The weak decay constants of heavy pseudoscalar
and vector mesons are also calculated. Our numerical results for the decay
constants and radiative decay widths for the heavy-flavored mesons are overall
in good agreement with the available experimental data as well as other
theoretical model calculations.
