The chromogenic complexes of ion association of 1-(4-Nitrophenyl)-3-(4-phenyl-azophenyl) triazene (m-NPPAPT) with cethyltrimethylammonium bromide (CTMAB), dodecyldimethylbenzylammo-nium bromide (DDMBAB), cetylpyrid-inium and bromide (CPB) tetradecylpyridinium bromide (TPB) were formed in the NaOH basic medium, respectively. Their association ratio with m-NPPAPT is 2∶1. The maximum absorption wavelength of the complexes for m-NPPAPT-CTMAB, m-NPPAPT-CPB, m-NPPAPT-TPB and m-NPPAPT-DDMBAB is at 538, 538, 625, 637 nm, respectively. The apparent mol...