  Recently reported anomalies in various $B$ meson decays and also in the
anomalous magnetic moment of muon $(g-2)$ motivate us to consider a particular
extension of the standard model incorporating new interactions in lepton and
quark sectors simultaneously. Our minimal choice would be leptoquark. In
particular, we take vector leptoquark ($U_1$) and comprehensively study all
related observables including ${(g-2)_{\mu}},\ R_{K^{(*)}},\ R_{D^{(*)}}$, $B
\to (K) \ell \ell' $ where $\ell\ell'$ are various combinations of $\mu$ and
$\tau$, and also lepton flavor violation in the $\tau$ decays.
