Abstract Nucleophilic addition of alkyl‐ and benzylthiols to benzoquinone diimine ( 1 ) gave the corresponding 3‐alkylthio‐ or 3‐benzylthio‐1,4‐phenylenediamines ( 2 – 5 ). However, addition of aryl‐ or heteroarylthiols to 1 formed 2‐arylthio‐ or 2‐heteroarylthio‐1,4‐phenylenediamines ( 6 – 14 ). The structures of 2 – 14 , obtained in 55–91% yields, were confirmed in CDCl 3 or DMSO‐ d 6 solution using 1D (NOE difference, coupled 13 C NMR spectra, APT and DEPT) and 2D NMR techniques DQCOSY, NOESY, HETCOR and heteronuclear multiple bond coherence (HMBC) that resulted in unambiguous proton and carbon NMR resonance assignments. The substituent‐induced 13 C NMR chemical shift differences were calculated in 2 – 14 relative to carbon atoms in the model compound N 1 ‐(1,3‐dimethylbutyl)‐ N 4 ‐phenyl‐1,4‐phenylenediamine (DMBPPD) ( 15 ) (a reduced form of benzoquinone diimine). Copyright © 2004 John Wiley & Sons, Ltd.