Reactions of azines with bifunctional nucleophiles can give rise to several cycloadducts, the structure depending on the nature of reagents, the structure of the azine substrate, and the reaction conditions. Three types of cycloadducts are proposed to be formed in reactions of azines with such 1,3-N,C-dinucleophiles as acetamidines and acetimino esters. Ortho-cyclization products can usually be isolated, while meta- and para-bridged cycloadducts are unstable and are often transformed into other heterocyclic systems. Their presence as intermediates can, however, often is rationalized by spectroscopic methods or 15N-labeling studies. Many of the reactions discussed provide a very convenient synthetic route to a great variety of azine derivatives. It seems to be a very interesting and promising area of heterocyclic chemistry and there is no doubt that further investigations into this field also allow new syntheses of useful compounds to be developed.