5-Aza-7-deazapurine or imidazo[1,2-a][1,3,5]triazine[1] is a heterocyclic aromatic organic compound that consists of a s-triazine ring fused to an imidazole ring.

However, in 5-aza-7-deazapurine, N-9 of five-membered ring does not bond with hydrogen.

So 5-aza-7-deazapurine derivatives must have an exocyclic substituent with a double bond to bind a sugar residue.

[2] 5-Aza-7-deazapurine nucleosides may have an oxo, thioxo, or a imine group.

Notable derivatives of this molecule include 5-aza-7-deazaguanine,[2] which is a nucleobase of hachimoji DNA.