  Motivated by the recently reported diphoton excess at 750 GeV observed by
both CMS and ATLAS, we study string-based particle physics models which can
accommodate this signal. Quite remarkably, although Grand Unified Theories in
F-theory tend to impose tight restrictions on candidate extra sectors, the case
of a probe D3-brane near an E-type Yukawa point naturally leads to a class of
strongly coupled models capable of accommodating the observed signature. In
these models, the visible sector is realized by intersecting 7-branes, and the
750 GeV resonance is a scalar modulus associated with motion of the D3-brane in
the direction transverse to the Standard Model 7-branes. Integrating out heavy
3-7 string messenger states leads to dimension five operators for gluon fusion
production and diphoton decays. Due to the unified structure of interactions,
these models also predict that there should be additional decay channels to ZZ
and Z gamma. We also comment on models with distorted unification, where both
the production mechanism and decay channels can differ.
