To 1mg of 1,1,2-trimethyl-1H-benzo[e]indole [marked as 1, Scheme-1] 0.5 mg of methyl iodide was added in the presence of acetonitrile and continuously stirred at 80˚C overnight. The obtained product from the overnight reaction 1,1,2-trimethyl-1H-benzo[e]indolium iodide (5.00 mmol) was mixed with syringaldehyde [marked as 2, Scheme-1] (5.00 mmol) along with 5.0 ml ethanol. Later, 0.5 ml of piperidine was added and refluxed for 4 hours at 80˚C. After cooling to room temperature, a brown solid precipitate was obtained. The precipitated brown solid was filtered and purified by column chromatography using Dichloromethane/Methanol as eluent to yield a glittery brown solid (Mito-pH2 dye). -Thin Layer Chromatography silica gel 60G F254 plates analysis showed a single fluorescent spot under the UV light after the completion of reaction. The scheme-1 outlines the synthetic pathway for the fluorescent probe Mito-pH2. ). M/Z was calculated for C25H26NO3 [M] + 388 and found using ESI mass-spectrometry determination 388.19 (Figure ). The melting point of Mito-pH2 dye was found to be 259 ˚C.