The powerful technique of microfluidics is applied for the first time to investigate the crystallization behavior and nucleation kinetics of monodisperse organic melt droplets in the range of a few nanoliters. Multiple characteristic time scales in the fraction of (un)crystallized droplets are found. We interpret these findings regarding mechanisms discussed in microfluidics or oil-in-water emulsions and with the help of inverse Laplace transformation. Heterogeneous active centers, for example, various catalytic impurities, cause fast nucleation in multiple droplet populations with different rates. The nucleation of the remaining droplets in the later stage of the experiment is dominated by only one, slower nucleation rate. The related mechanism is most likely surfactant-driven heterogeneous nucleation at the surface or in the droplet volume. Homogeneous nucleation is excluded at this droplet size and the supercooling values examined. Hexadecane (C16) and ethylene glycol distearate (EGDS) are used as exemplary organic melt substances. Our results prove that the application of microfluidics to organic melt droplets enables an optical examination of monodisperse droplets without droplet interactions to study nucleation. This provides new opportunities to investigate fundamental parameters in the field of emulsion crystallization.