4-Thiazolodinone-1, 1-dioxide (TZ) consisting of 5-membered heterocyclic ring system is very interesting skeleton from the viewpoint of dye formation, because it possesses an active methylene at 5-position in its ring system. Eight kinds of TZ derivatives were synthesized and their coupling reactivity with quinonediimine (QDI) was investigated. Investigation of these TZ derivatives revealed that, (i) TZ derivatives could be coupled with QDI resulting in azomethine magenta dyes, (ii) these dyes are hypsochromically shifted in hue, compared with dyes obtained from conventional pyrazolone (PR) magenta couplers, (iii) they also have undesirable secondary spectral absorption peaks as well as the dyes obtained from PR couplers. Here in, we report on the relationship between the electronic effect of the substituents and λ_max of dyes formed from TZ derivatives. In addition, the absorption spectra of TZ derivatives in azomethine dyes are compared with those of PR couplers.