Assignment of ir-spectra of 1-nitro-, 1,5-dinitro-, 1, 4, 5, 8-tetranitro- and 1, 3, 6, 8-tetranit- ronaphthalene were investigated. The formation of CT — complexes of the last compound with some polynuclear aromatic compounds were studied, and the ir-spectra of the addition com« pounds were correlated with their structure.