Photo‐induced generation of merocyanines from the corresponding spiropyrans having strong para‐electron withdrawing groups could be observed with naked eyes and conventional UV‐visible spectroscopy. But absence of such groups or presence of weak electron withdrawing groups make the molecular switch a non‐activated system towards photoisomerization. And thus the colored photo‐merocyanine isomers of non‐activated spiropyrans could be monitored exclusively by ultrafast spectroscopy. Here, we describe a novel way of generating metastable merocyanines of non‐activated spiropyrans ‐ via dilution of the corresponding protonated isomers in suitable solvent systems. And studied the thermal kinetics of the colored isomers at an observable time scale via conventional spectroscopy. Protonated merocyanines of non‐activated spiropyrans with a butyl sulfonate group on the nitrogen of the indoline moiety upon dilution with polar aprotic solvents, such as DMF produce the corresponding colored merocyanines with sufficiently high accumulation so that it could easily be detected by human eyes and UV‐visible spectroscopy. Whereas, dilution of the same protonated merocyanines with moderately polar solvents like acetone provide no detectable merocyanine formation. Although acid dissociation at higher dilution seems obvious, but selection of proper solvent is the key factor. Notably, BIPS‐photoacids are known to exist predominantly as undissociated protonated merocyanines in water and methanol.

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