Jabłoński initially studied the violin at Warsaw Conservatory, under the virtuoso Stanisław Barcewicz, but later switched to science.

He received a Ph.D. from the University of Warsaw in 1930, writing a thesis On the influence of the change of the wavelength of excitation light on the fluorescence spectra.

His thesis was On the influence of intermolecular interactions on the absorption and emission of light, the subject to which he would devote the rest of his life.

Jabłoński was a pioneer of molecular photophysics, creating the concept of the "luminescent centre" and his own theories of concentrational quenching and depolarization of photoluminescence.

Fluorescence is illustrated schematically with the classical Jablonski diagram, first proposed by Jabłoński in 1933[2] to describe absorption and emission of light.