A review of reactions of quaternary salts of 2,3-dimethylquinoxaline, especially those leading to indigoid or quinoid chromogens, is combined with the presentation of recent results. Part IV includes a review of dihydronaphtho[1,2-b]phenazinones and of dihydroanthraceno[1,2-b]phenazinones, which were readily obtained by ring closure in quinonylmethane dyes. The synthesis of thirty dihydronaphtho-[1,2-b] phenazinones and of three dihydroquinolino[1,2-b]phenazinones is then described. 1,2,3-Trimethyl-6-X-quinoxalinium-perchlorates (X = NO 2, SO 2CH 3, CN, or CF 3) were reacted with (a) 2,3-dichloro-, (b) 2,3-dibromo-, (c) 2,3-dichloro-5-nitro-, (d) hexachloro-naphthoquinone, or (e) 6,7-dichloro-5,6-quinolinequinone respectively. In the case of (d), a tetrachloro-5-hydroxy-dihydronaphtho [1,2-b]phenazinone was obtained as a by-product. By reacting the quinone given under (a) above with 1,2,3-trimethyl-6-mesyl-quinoxaliniumperchlorate and NaCN, 2-cyano-3-( 1,3-dimethyl-6-cyano-1, 2-dihydroquinoxaline-2-ylidenemethyl)-1,4-naphthoquinone was obtained, which yielded 41% of the appropriate phenazinone on ring closure with CH 3COOH and Et 3N. Dihydronaphtho[1,2-b]phenazinones derived from naphthoquinone (unsubstituted) or 2-methyl-naphthoquinone are less readily available. On the other hand, a pentachloronaphthophenazinole was obtained by reacting the quinone (a) with 2,3-dimethyl-5,6,7,8-tetrachloro-quinoxaline. Hydroxylation of 6-chloro-8-cyclohexyl-11-methyl-5,8-dihydro[1,2-b]naphthophenazinone with NaOH in DMSO-H 2O resulted in the isolation of the appropriate 14-hydroxy-derivative.