Macrocyclic and polymeric imines 5,5′ and 6,6′ are obtained in excellent yields by template-free polycondensation of 1,6-bis(4-formylbenzoyloxy)hexane (1) with commercially available 4,4′-methylene-bis(cyclohexylamine) (2) and with bis(2-amino-2-methylprop-1-yl)adipate dihydrochloride (4), respectively. The degree of macrocyclization during imine synthesis strongly depends on the diamine. Matrix-assisted laser desorption–ionization time-of-flight (MALDI-TOF) mass spectrometry analysis and gel permeation chromatography (GPC) measurements show that (2) leads to more macrocyclic adducts than (4). The subsequent meta-chloroperoxybenzoic acid oxidation of polyimines 5,5′ and 6,6′ ( = 1650–11 200 g mol−1, = 3800–27 350 g mol−1) yields the corresponding polyoxaziridines 7,7′ and 8,8′ consisting of macrocyclic and linear polymeric structures ( = 1750–8050 g mol−1, = 3250–15 800 g mol−1). The synthesized polyoxaziridines are relatively stable and storable at room temperature.