  We conjecture infrared emergent $\mathcal{N}=4$ supersymmetry for a class of
three-dimensional $\mathcal{N}=2$ $U(1)$ gauge theories coupled with a single
chiral multiplet. One example is the case where $U(1)$ gauge group has the
Chern-Simons level $-\frac{3}2$ and the chiral multiplet has gauge charge $+1$.
Other examples are related to this example either by known dualities or
rescaling the Abelian gauge field. We give three independent evidences for the
conjecture: 1) exact match between the central charges of the $U(1)$ R-symmetry
current and the $U(1)$ topological symmetry current, 2) semi-classical
construction of the $\mathcal{N}=4$ stress-tensor multiplet, and 3) an IR
duality between a direct product of the two copies of the 3d theory on the one
hand, and an $\mathcal{N}=4$ theory obtained by gauging the diagonal $SU(2)$
flavor symmetry of the $T[SU(2)]$ theory, on the other. The duality in 3)
follows from geometrical aspects of the 3d-3d correspondence.
