2-[1-(Triphenylmethyl)-1H-imidazol-4-yl]benzaldehyde is an intermediate in synthesizing NLG919-d10 (N630002). It is a isotope labelled analog of NLG919 (N630000). NLG919 is a potent indoleamine-2,3-dioxygenase (IDO) pathway inhibitor and is suitable for the treatment of immunosuppression associated with cancer.