  We study the possibility of explaining the recently reported 750 GeV
di-photon excess at LHC within the framework of a left-right symmetric model.
The 750 GeV neutral scalar in the model is dominantly an admixture of neutral
components of scalar bidoublets with a tiny fraction of neutral scalar triplet.
Incorporating $SU(2)$ septuplet scalar pairs into the model, we enhance the
partial decay width of the 750 GeV neutral scalar into di-photons through
charged septuplet components in loop while keeping the neutral septuplet
components as subdominant dark matter candidates. The model also predicts the
decay width of the 750 GeV scalar to be around 36 GeV to be either confirmed or
ruled out by future LHC data. The requirement of producing the correct
di-photon signal automatically keeps the septuplet dark matter abundance
subdominant in agreement with bounds from direct and indirect detection
experiments. We then briefly discuss different possibilities to account for the
remaining dark matter component of the Universe in terms of other particle
candidates whose stability arise either due to remnant discrete symmetry after
spontaneous breaking of $U(1)_{B-L}$ or due to high $SU(2)$-dimension
forbidding their decay into lighter particles.
