  We study the diphoton excesses near $750$ GeV recently reported by the ATLAS
and CMS collaborations within the context of a phenomenologically interesting
intersecting/magnetized D-brane model on a toroidal orientifold. It is shown
that the model contains a SM singlet scalar as well as vector-like quarks and
leptons. In addition, it is shown that the singlet scalar has Yukawa couplings
with vector-like quarks and leptons such that it may be produced in
proton-proton collisions via gluon fusion as well as decay to diphotons through
loops involving the vector-like quarks. Moreover, the required vector-like
quarks and leptons may appear in complete $SU(5)$ multiplets so that gauge
coupling unification may be maintained. Finally, it is shown that the diphoton
signal may be explained within the model.
