  The ATLAS and CMS collaborations recently recorded possible di-photon excess
at 750 GeV and a less significant di-boson excess around 1.9 TeV. Such excesses
may be produced in heterotic-string derived Z' models, where the di-photon
excess may be connected with the Standard Model singlet scalar responsible for
the Z' symmetry breaking, whereas the di-boson excess arises from production of
the extra vector boson. Additional vector-like states in the string Z' model
are instrumental to explain the relatively large width of the di-photon events
and mandated by anomaly cancellation to be in the vicinity of the Z' breaking
scale. Wilson line breaking of the non-Abelian gauge symmetries in the string
models naturally gives rise to dark matter candidates. Future collider
experiments will discriminate between the high-scale heterotic-string models,
which preserve the perturbative unification paradigm indicated by the Standard
Model data, versus the low scale string models. We also discuss the possibility
for the production of the di-photon events with high scale $U(1)_{Z^\prime}$
breaking.
