AbstractThe synthesis and structure analysis of the unknown 1H‐imidazo[1,2‐a]imidazole (1) is described. The preparation involves alkylation of 2‐aminoimidazole with bromoacetaldehyde diethyl acetal and subsequent hydrolysis and cyclization with hydrochloric acid. The structure was characterized by mass spectrometry and by1H‐,15N‐ and13C‐nmr of1and by1H‐nmr of its 1‐benzyl derivative8. An independent synthesis of8was accomplishedviacyclization of 2‐(N‐dichloroethyl‐N‐ben