Diazotization and diazocoupling reactions of para-aminobenzene-1-sulfonyl azide and para-aminobenzene-1-sulfonyl amide with cyclic amines of various ring sizes (pyrrolidine, piperidine, 4-methylpiperidine, N-methylpiperazine, morpholine and hexamethyleneimine over eco-friendly clay catalysts, HZSM-5 and sulphated zirconia are described. These inexpensive, noncorrosive and reusable catalysts appear to exhibit bifunctional catalytic properties for these reactions. No considerable decreases in the efficiency of the catalysts were observed after four cycles of operation. The new method totally avoids the use of acid, alkali or toxic solvents in diazotization and diazocoupling reactions. (C) 2007 Elsevier B.V. All rights reserved.