Here we report a robust and operationally simple base-promoted N–N bond cleavage by means of a Michael type addition/E1cb elimination sequence, assisted by 1,2-diaza-1,3-dienes (DDs) on a series of N-aminoheterocycles, to obtain exclusively the corresponding NH-free hetero-ring derivatives, under very mild conditions. The method developed highlights a new and hitherto unexplored face of DDs and opens up fascinating new opportunities for their application in organic chemistry.