The effect of the structure of a number of new laser media based on heteryl-coumarins on their spectral and lasing characteristics is studied under conditions of coherent nanosecond and microsecond lamp pumping. The effect of triazole, oxadiazole, and thiazole heterocycles in the structure of coumarin molecules on the spectral, lasing, and photochemical properties of their ethanol solutions has been studied. The analysis of the influence of heteroatoms, heterocyclic radicals, and an aryl fragment in the conjugation chain on the electron density distribution in the structure of coumarin molecules is carried out. It was shown, that triazole and oxadiazole heterocycles provide better lasing ability and photostability of the compounds under study, which made it possible to create new laser media generating radiation in the spectral range 490-560 nm with a sufficiently high efficiency.