  We calculate the magnetic dipole moment of the newly observed charged
hidden-charmed open strange $ Z_{cs}(3985)^- $ state, recently observed by the
BESIII Collaboration. Based on the information provided by the experiment and
theoretical studies followed the observation, we assign the quantum numbers $
J^{P} = 1^{+}$ and the quark composition $ c \bar c s\bar u $ to this state and
estimate the magnetic dipole moment of this resonance in both the compact
diquark-antidiquark and molecular pictures. We apply the light cone QCD
formalism and use the distribution amplitudes of the on-shell photon with
different twists. The obtained results can help experimental groups aiming to
measure the electromagnetic properties of such states, comparison of which with
the theoretical predictions can help us in determination of the exact nature,
substructure and quantum numbers of this strange tetraquark.
