A process is for hydrocracking a dealkylated aromatic stream in the presence of a hydrogen stream and a hydrocracking catalyst to provide a hydrocracked stream and hydrotreating a diesel stream and the hydrocracked stream together over a hydrotreating catalyst to provide a hydrotreated diesel stream. The two streams are processed together without cracking the valuable diesel boiling hydrocarbons to below the diesel range and also upgrading the cetane value of the dealkylated aromatic stream.