  We report on the single crystal properties of the novel U$_{2}$RhIn$_{8}$
compound studied in the context of parent URhIn$_{5}$ and UIn$_{3}$ systems.
The compounds were prepared by In self-flux method. U$_{2}$RhIn$_{8}$ adopts
the Ho$_{2}$CoGa$_{8}$-type structure with lattice parameters a $= 4.6056(6)$
\AA\ and c $= 11.9911(15)$ \AA. The behavior of U$_{2}$RhIn$_{8}$ strongly
resembles that of the related URhIn$_{5}$ and UIn$_{3}$ with respect to
magnetization, specific heat and resistivity except for magnetocrystalline
anisotropy developing with lowering dimensionality in the series UIn$_{3}$ vs.
U$_{2}$RhIn$_{8}$ and URhIn$_{5}$. U$_{2}$RhIn$_{8}$ orders
antiferromagnetically below T$_{\textrm{N}}$ $= 117$ K and exhibits a slightly
enhanced Sommerfeld coefficient $\gamma = 47$ mJ$\cdot$mol$^{-1}\cdot$K$^{-2}$.
Magnetic field leaves the value of N\'{e}el temperature for both URhIn$_{5}$
and U$_{2}$RhIn$_{8}$ unaffected up to 9 T. On the other hand, T$_{\textrm{N}}$
is increasing with applying hydrostatic pressure up to 3.2 GPa. The weak
temperature dependence of $\chi(T)$ in all studied compounds might be
attributed to the mainly itinerant nature of 5f electrons. The character of
uranium 5f electron states of U$_{2}$RhIn$_{8}$ was studied by first principles
calculations based on the density functional theory. The overall phase diagram
of U$_{2}$RhIn$_{8}$ is discussed in the context of magnetism in the related
URhX$_{5}$ and UX$_{3}$ (X = In, Ga) compounds.
