A series of 10-aryl substituted azo dyes were synthesized by coupling of β-naphthol, catechol, and quinol with different aromatic amines. The synthetic compounds were screened for their in vitro antimicrobial, antioxidant, and anti-inflammatory activities. The characterization of the synthesized compounds was carried out by UV, IR, 1H NMR and Mass spectroscopy. 13C NMR was employed to confirm the structural identity of some of the compounds.  After screening for the presence of antimicrobial constituents in the azo compounds using HTSPOTi culture method, quinol compounds 7 [(E)-2(2nitrophenyl) diazenyl) benzene-1,4-diol] and 10 [(E)-2-(3-nitrophenyl) diazinyl) benzene-1,4-diol] were the most active in terms of broad spectrum activity against  Gram-positives [Staphylococcus aureus (ATCC 25923), Streptococcus pyrogenes (clinical strain), Enterococcus faecalis (ATCC 29212)],, Gram-negatives [Salmonella typhi (clinical strain), Escherichia coli (ATCC 251922)] and Pseudomonas aeruginosa (ATCC 27853)  and the Candida albicans at minimum inhibitory concentrations of 15.63-31.25 µg/mL. A quinol derivative, [(E)-2-(2nitrophenyl) diazinyl) benzene-1, 4-diol], exhibited the best anti-inflammatory activity in the heat-denatured egg albumin assay. Compounds [ethyl (Z)-4-(3-hydroxynapthalen-1-yl (diazinyl) benzoate] and (E)-2-((3-nitrophenyl) diazenyl) benzene-1,4-diol showed high DPPH free radical scavenging activity during the antioxidant assay.

4-(2-(2,4-Dinitrophenyl) hydrazone) methyl)-2 methoxy phenol (IND-X) and 4-(2-(2, 4-dinitrophenylhydrazono) methyl) benzene-1,3-diol (IND-Y) were synthesised by condensation reactions with 2,4-dinitrinophenylhydrazine and were observed to possess acid-base indicator properties. The study was conducted to explore and verify their use in different analytical situations and, consequently, validate them. Analysis of their use in acid-base titrations between strong acids/strong bases and weak acids/strong bases as well as pharmaceutical applications in the assay of ibuprofen pure powder and batch of ibuprofen tablets (400 mg) using standard methods in the British Pharmacopoeia (2020) was all considered. The validations were performed by the International Conference on Harmonisation of Technical Requirements for the registration of Pharmaceuticals for Humans Q2 (R1) guidelines. The outcomes were statistically compared with existing conventional analytical approaches. Titrimetric data obtained were analyzed statistically by Student’s t-test and one-way ANOVA at a 95% confidence level. IND-X and IND-Y were shown to be similar in behaviour to phenolphthalein, methyl orange, and methyl red as visual indicators after preliminary evidence of sharp colour changes in acid, alkaline, and neutral pH solutions. The use of the two indicators in the assay of ibuprofen powder and tablets has also been established. The validation parameters considered were found to be consistent with respective acceptance criteria for analytical purposes. IND-X and IND-Y are therefore proposed as alternative acid-base indicators to methyl red, methyl orange, and phenolphthalein for routine volumetric analysis in students’ laboratory experiments. They also serve as alternative indicators to phenolphthalein for the titrimetric analysis of ibuprofen-based samples and products.