The phosphorescence and optically detected magnetic resonance (ODMR) spectra of 4,4'-dimethoxy-4,4'-dimethyl-3,3'-dibromo- and 2,2'-diazabenzophenone were measured. For 4,4'-dimethoxybenzophenone 2 X-traps were found. The zero-field splitting (ZFS) parameters and the phosphorescence decay consts. indicate that the lowest triplet states have mainly np* character. The effects of the substituents on the ZFS parameters cannot be explained via spin-orbit coupling with only nearby excited states.