  Among radio galaxies, compact sources are a class of objects not yet well
understood, and most of them cannot be included in classical populations of
compact radio sources (flat spectrum AGN or compact steep spectrum sources).
Our main goal is to analyze the radio and optical properties of a sample of
compact sources and compare them with FRI/FRII extended radio galaxies. We
selected in the Bologna Complete Sample a sub sample of Compact sources, naming
it the C BCS sample. We collected new and literature sub-arcsecond resolution
multi-frequency VLA images and optical data. We compared total and nuclear
radio power with optical emission line measurements. The [OIII] luminosity -
408 MHz total power relation found in High and Low excitation galaxies, as well
as in young (CSS) sources, holds also for the C BCSs. However, C BCSs present
higher [OIII] luminosity than expected at a given total radio power, and they
show the same correlation of Core Radio Galaxies, but with a higher radio
power. C BCSs appear to be the high power tail of Core Radio Galaxies. For most
of the C BCSs, the morphology seems to be strongly dependent to the presence of
dense environments (e.g. cluster or HI-rich galaxies) and to a low age or
restarted radio activity.
