  With the potential prospects of the ${\Upsilon}(nS)$ at high-luminosity
dedicated heavy-flavor factories, the color-favored ${\Upsilon}(nS)$ ${\to}$
$B_{c}{\pi}$, $B_{c}K$ weak decays are studied with the pQCD approach. It is
found that branching ratios for the ${\Upsilon}(nS)$ ${\to}$ $B_{c}{\pi}$ decay
are as large as the order of ${\cal O}(10^{-11})$, which might be measured
promisingly by the future experiments.
