I want to change pH of an organic solvent 'dibenzyl ether'. Being it is water immiscible NaOH/KOH does't work. is their any other way to adjust pH of this solvent?
If you want to make the "pH basic of dibenzyl ether" you can add an organic base for example Et3N or (iPr)2EtN. Remember that the pH scale is defined for water as the solvent and this is not used for organic solvents.
Just following up on Vicente's good recommendation to you. You may likewise use organic acids such as benzoic acid (or trifluoroacetic acid or formic acid or acetic acid) to adjust the acidity of your diluent.