Stimuli-responsive luminescent soft materials are of current interest owing to their tunable processability for encryption, sensing, and multimodal security applications. Herein, a tripodal carboxylic acid based triazine mediated linker (3,3′,3″-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzoic acid) has been used to synthesize photochromic coordination driven soft gel (CSG) with Tb(III)/Eu(III) ions. Tuning of the stoichiometric ratios exhibited a "chameleonlike" behavior upon exposure to UV lights and led to origination of white lightemitting materials. The CSGs were applied in robust anticounterfeit applications through security ink, stamping, and painting on different surfaces under variable conditions. Along with this, terbium-based CSG was used as an optical sensor for selective detection of antibiotics (nitrofurantoin (NFT), LOD = 64.25 ppb) and nitroexplosive (2,4,6-trinitrophenol, LOD = 24.5 ppb) from an aqueous medium using photoluminescence spectroscopy. RGB-mediated smartphone-based detection for nitroexplosive and antibiotic detection in real water samples aided this as a smart sensor to emphasize the real-time applicability.