  We study the constraints imposed by superconformal symmetry, crossing
symmetry, and unitarity for theories with four supercharges in spacetime
dimension $2\leq d\leq 4$. We show how superconformal algebras with four
Poincar\'{e} supercharges can be treated in a formalism applicable to any, in
principle continuous, value of $d$ and use this to construct the superconformal
blocks for any $d\leq 4$. We then use numerical bootstrap techniques to derive
upper bounds on the conformal dimension of the first unprotected operator
appearing in the OPE of a chiral and an anti-chiral superconformal primary. We
obtain an intriguing structure of three distinct kinks. We argue that one of
the kinks smoothly interpolates between the $d=2$, $\mathcal N=(2,2)$ minimal
model with central charge $c=1$ and the theory of a free chiral multiplet in
$d=4$, passing through the critical Wess-Zumino model with cubic superpotential
in intermediate dimensions.
