The intense luminescence of SiOC layers is studied and its dependence on the parameters of the thermal annealing process elucidated. Although the emission of SiOC is bright enough to be interesting for practical applications, this material is even more promising as a host matrix for optically active Eu ions. Indeed, when incorporated in a SiOC matrix, Eu(3+) ions are efficiently reduced to Eu(2+), producing a very strong visible luminescence peaked at 440 nm. Eu(2+) ions benefit also of the occurrence of an energy transfer mechanism involving the matrix, which increases the efficiency of photon absorption for exciting wavelengths shorter than 300 nm. We evaluate that Eu doping of SiOC produces an enhancement of the luminescence intensity at 440 nm accounting for about a factor of 15. These properties open the way to new promising perspectives for the application of Eu-doped materials in photonic and lighting technologies.