A new tripodal chelator 2,2′,2′′-((1E,1′E,1′'E)-(nitrilotris(ethane-2,1-diyl)tris(azanylylidene))-tris(methanylylidene))tris(quinolin-8-ol), TREN2OX, containing three 8-hydrixyquinoline (8-HQ) units appended to a tris(2-aminoethyl)amine (TREN) skeleton has been synthesized and characterized through elemental analysis (CHN), FT-IR, NMR (1H, 13C) and ESI mass spectrometry. The interaction of the ligand with the proton, Fe3+ and Al3+ was studied by potentiometric and spectrophotometric methods. The solution thermodynamic formation constants could be evaluated in an aqueous solution at 298±1 K. Six protonation constants were evaluated with formation constants ranging from 1.50 to 9.86, corroborating three nitrogen atoms of the 8-hydroxyquinoline ring and three phenolate groups. With iron and aluminium, the ligand forms [FeL], [FeLH2], [FeLH3] and [AlL], [AlLH3] complexes having log β as 43.64, 24.92, 53.82, and 29.20, 52.85 respectively. The absorbance spectra of TREN2OX and its complexes showed variation in spectral behavior with a change in pH. In the aqueous solution, the ligand showed an enhancement in emission at 460 nm at neutral pH 7.0, while in acidic and basic pH, the fluorescence was quenched with bathochromic shift implying its utility as an OFF-ON-OFF pH molecular sensor. Interestingly, the fluorescence of TREN2OX showed enhancement in the presence of Al3+, while a reverse phenomenon (quenching) was observed for Fe3+, indicating that the ligand can behave as a metal sensor for both the metal ions, one as “ON” type and the other as “OFF” type. The DFT was used to predict molecular geometry, IR, NMR, absorbance, emissions spectra for all possible species for the ligand and its ligand-proton and ligand-metal complexes. The structure, bonding, and electronic behavior, including the electronic transitions, were evaluated by studying FMO, EDA, ETS-NOCV, and NTO in the ground and excited state geometry.