“…This work is a continuation of our studies focusing on the paramount goal of supramolecular exploration of biologically active systems, especially short peptides and modified amino acids ( Główka, et al, 2004 ; Główka, et al, 2005 ; Główka, et al, 2007 ; Olczak, et al, 2007 ; Olczak, et al, 2010 ; Remko, et al, 2011 ; Bojarska et al, 2012a ; Bojarska et al, 2012b ; Remko et al, 2013 ; Bojarska et al, 2013a ; Bojarska et al, 2013b ; Bojarska et al, 2013c ; Bojarska et al, 2014 ; Bojarska et al, 2015 ; Bojarska and Maniukiewicz, 2015 ; Remko et al, 2015 ; Bojarska et al, 2016 ; Bojarska et al, 2018a ; Bojarska et al, 2018b ; Bojarska et al, 2019a ; Bojarska et al, 2019b ; Bojarska et al, 2019c ; Bojarska et al, 2019d ; Bojarska et al, 2019e ; Bojarska et al, 2020a ; Bojarska et al, 2020b ; Bojarska et al, 2020c ; Bojarska et al, 2020d ). The article is the first one, according to our knowledge, to gain deep supramolecular insight into the very popular drug DFMO ( 1 ) ( Supplementary Figure S1 ), an ornithine derivative ( Bojarska et al, 2020b ), which is still being developed as a promising broad-spectrum therapeutic agent. It is surprising that its crystal structure has not been determined so far, although the compound has been known for almost half a century.…”