Surface brightness profiles for Ellipticals with a range of luminosity. The x axis is R1/4 in kpc1/4. Clearly, more luminous galaxies are bigger, but also larger n-index since if the profile curves down the n-index is less than 4, but if it curves up it is more than 4.
Clear trend for more luminous Elliptical galaxies to have higher n-index (more concentrated profiles). Note the low luminosity dwarf spheroids have Sersic n in the same range as for disks. [Figure 33 from Kormendy et al 2006 o-link).