The next-to-minimal supersymmetric standard model (NMSSM)
with an extended Higgs sector offers at least one Higgs boson as the
Standard model (SM) like Higgs with a mass around 125 GeV.
We revisit the mass spectrum and couplings of non-SM-like
Higgs bosons taking into consideration most relevant constraints.
We evaluate the rates of productions of these non-SM-like Higgs bosons at the LHC for a variety of decay channels corresonding to the allowed region of the parameter space. We notice that for a substantial region of the parameter space the two-photon decay mode has a remarkably
large rate. In this study we emphasize that this diphoton mode can be
exploited to find the non-SM-like Higgs bosons of the NMSSM
and can also be a potential avenue to distinguish the NMSSM from the MSSM.
We plan to present also detection possibility of light pseudoscalar
Higgs boson($A_1$) in the diphoton final states where $A_1$ is produced
via chargino-neutralino production. In this context we will present
signal sensitivity by computing the background in details
at the LHC with energy 13 TeV.