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• New chemo-dosimeter selectively and sensitively senses CN− via dual channel responses and Al(III) via CHEF effect. • Mechanism of CN− sensing involves deprotonation of phenolic -OH group followed by nucleophilic addition at imine C-atom. • 1H & 27Al NMR and mass spectral techniques reveal that Al(III) forms a 1:1 octahedral complex [Al(VDP1)(NO 3) 3 (H 2 O)]. • DFT and TD-DFT calculations confirm that weak fluorescence of the probe is due to CT character of the transition therein non-radiative decay dominates. • MTT assay indicates that the probe is less toxic to HeLa cells and could detect intracellular CN− and Al(III) ions by bioimaging. The selective and sensitive dual channel assay of CN− and fluorescence assay of Al(III) are reported using a simple organic probe (VDP1) in aqueous and non-aqueous media. The binding behaviours of these ionic analytes with VDP1 were studied using UV–Vis, fluorescence, (1H, 13C & 27Al) NMR and mass spectral techniques. VDP1 showed a highly selective change of colour and fluorescence enhancement with CN− ion immediately without interference from other anions. The experimental results revealed that the mechanism of CN− detection involves deprotonation of the phenolic -OH group followed by nucleophilic addition at the imine C-atom. The addition of Al(III) was found to enhance the fluorescence of VDP1 significantly through chelation-enhanced fluorescence effect (CHEF) by forming a 1:1 octahedral complex [Al(VDP1)(NO 3) 3 (H 2 O)]. The Density Functional Theory (DFT) and Time-dependent Density Functional Theory (TD-DFT) based theoretical calculations confirmed that the weak fluorescence of VDP1 is due to the charge transfer (CT) character of the transition in which non-radiative decay dominates. The theoretically computed optical properties matched well with that of experimental observations. The limits of detection (LOD) of these ionic analytes were also calculated and found to be much lower than the corresponding recommended limit set by the World Health Organization (WHO). MTT assay indicated that VDP1 is less toxic to HeLa cells and could detect intracellular CN− and Al(III) ions by bioimaging. [ABSTRACT FROM AUTHOR]