  We study various spectral properties of the Seidel matrix $S$ of a connected
chain graph. We prove that $-1$ is always an eigenvalue of $S$ and all other
eigenvalues of $S$ can have multiplicity at most two. We obtain the
multiplicity of the Seidel eigenvalue $-1$, minimum number of distinct
eigenvalues, eigenvalue bounds, characteristic polynomial, lower and upper
bounds of Seidel energy of a chain graph. It is also shown that the energy
bounds obtained here work better than the bounds conjectured by Haemers. We
also obtain the minimal Seidel energy for some special chain graphs of order
$n$. We also give a number of open problems.
