  We discuss an extended scalar model which explains the recent results of
diphoton excess at 750 GeV at LHC Run II experiments. An additional singlet
scalar boson with the mass of 750 GeV, which couples to top quarks via a
dimension five operator, is produced via gluon fusion and decays into two
photons via loop contributions of a number of (multiply) charged scalar bosons.
Origin of such a dimension five operator would be, for example, in the context
of composite Higgs models. The excess can be explained without contradicting
the data from LHC Run I and also theoretical consistencies such as perturbative
unitarity and charge non-breaking.
