Abstract We've investigated the annealing behaviour of the di-carbon centre (zero-phonon line at 969 meV or 7818 cm-1)in float zone and Czochralski silicon crystals. The break-up process is not the only way to destroy the di-carbon centres and it is shown that the presence of other defects may affect the annealing process. After the thermal destruction of the di-carbon centre, we've discovered many previously unreported carbon and oxygen related point defects. Their photolumiescence lines are observed. We suggest that the interstitial silicon atom is the defect trapped near but not ‘at' the di-carbon centre forming the satellite sublines at 951.16(7671), 952.98(7686), and 956.91meV (7717cm-1).