  We have investigated the structural properties and dynamical stability of
C$_3$N$_2$ hosting hydrogen as a guest atom. The calculations were performed
using the density functional theory (DFT) as implemented in Quantum espresso
code. The generalized gradient approximation approach was used throughout the
calculations presented here. We find that the guest atom leaves the lattice
constant of the host almost unchanged. We, therefore, noted that C$_3$N$_2$
remains dynamically stable when a single guest atom is inserted into its
cage-like structure. We also established that the guest vibrational modes are
low-lying modes that lower the acoustic bandwidth of C$_3$N$_2$.
