  Two-dimensional materials offer a unique range of magnetic, electronic and
mechanical properties which can be controlled by external stimuli. Pressure is
a particularly important stimulus, as it can be achieved readily and can
produce large responses, especially in low-dimensional materials. In this paper
we explore the pressure-dependence of the structural and magnetic properties of
a two-dimensional van der Waals (vdW) molecular framework antiferromagnet with
ferromagnetic layers, Ni(NCS)$_2$, up to 8.4 kbar. Through a combination of
X-ray and neutron diffraction analysis, we find that Ni(NCS)$_2$ is
significantly more compressible than comparable vdW metal halides, and its
response is anisotropic not only out of the plane, but also within the layers.
Using bulk magnetisation and neutron diffraction data, we show that the ambient
layered antiferromagnetic phase is maintained up to the largest investigated
pressure, but with an enhanced N\'eel temperature, $T_\mathrm{N}$, ($\Delta
T_\mathrm{N} / T_\mathrm{N} = +19$ %) and a large pressure sensitivity ($Q =
\frac{1}{T_\mathrm{N}} \frac{\mathrm{d}T_\mathrm{N}}{\mathrm{d}P} = +2.3$ %
kbar$^{-1}$), one of the larger values of magnetic pressure responsiveness for
a vdW material. Density functional theory calculations suggest that this is due
to increasing three-dimensionality. These results provide some of the first
insights into the pressure response of molecular framework vdW magnets and
suggest investigation of other molecular framework vdW magnets might uncover
contenders for future pressure-switchable devices.
