Zinquin AM ester is a zinc-sensitive, cell-impermeable fluorescent probe. Zinc is the second most abundant transition metal in the body and it is essential as catalytic, structural and regulatory ion. Zinc ions are involved in homeostasis, immune responses, oxidative stress, apoptosis and aging. Zinc has been proposed to function as a conventional neurotransmitter for the presynaptic neuron and as a transmembrane signal to traverse the postsynaptic neuron. Aberrant zinc metabolism is associated with many neurological diseases including Alzheimer’s disease, Parkinson’s disease and epilepsy. The most suitable technique for in vivo monitoring of zinc has been proven to be fluorescence imaging.