The gold-catalyzed interplay between cyanamides and ynamides demonstrates condition-dependent mechanistic dichotomy. [2+2+2] Cycloaddition proceeds under kinetically controlled conditions to give 2,4,6-triaminopyrimidines (19 examples, up to 99%). Under thermodynamically controlled conditions, the reactivity switches from [2+2+2]- to [4+2] cycloaddition; the latter [4+2] reaction accomplishes 1,3-diaminoisoquinolines (19 examples, up to 97%). The advantages of both methods include regioselectivity, mild reaction conditions (even for the thermodynamically controlled [4+2] reaction) and the possibility of introducing a variety of dialkyl, diaryl, and heterocyclic amino substituents into the target pyrimidine and isoquinoline cores. The reactions were conducted on gram scales and the versatility of the obtained products was demonstrated by post-functionalizations. (Figure presented.).