1,7-Phenanthroline has inhibitory effect on germination and growth of plants. 1,7-Phenanthroline is an aza-analog of phenanthrene, was found to be mutagenic in the Ames test using Salmonella typhimurium TA100 in the presence of a rat liver S9 fraction. Supramolecular assemblies of 1,2,4,5-benzenetetracarboxylic acid with 1,7-phenanthroline (aza donor molecule) were investigated.