  A data mining study of electronic Kohn-Sham band structures was performed to
identify Dirac materials within the Organic Materials Database (OMDB). Out of
that, the 3-dimensional organic crystal
5,6-bis(trifluoromethyl)-2-methoxy-1$H$-1,3-diazepine was found to host
different Dirac line-nodes within the band structure. From a group theoretical
analysis, it is possible to distinguish between Dirac line-nodes occurring due
to 2-fold degenerate energy levels protected by the monoclinic crystalline
symmetry and 2-fold degenerate accidental crossings protected by the topology
of the electronic band structure. The obtained results can be generalized to
all materials having the space group $P2_1/c$ (No. 14, $C^5_{2h}$) by
introducing three distinct topological classes.
