In order to investigate a potential phosphor material for solid state illumination applications, we developed a series of green light emanating Er3+ doped GdSr2AlO5 (GSA) phosphors using the gel-combustion process. Diffraction investigation reveals that the fabricated nanophosphors are of tetragonal symmetry with I4/mcm (140) space group. SEM and TEM micrograph defines the almost smooth, irregular and agglomerated morphology with particle size in nano domain. Calculated band gap energy (5.769 eV) of the optimized sample depicts it's almost semiconductor behaviour. EDX spectral lines affirm the composition and pure synthesis of the prepared nanophosphors. The emission spectra of all doped samples consists of one most intense emission band at 550 nm with 4S3/2→4I15/2 transition and three very less intense bands at 406, 520 and 665 nm with 2H9/2→4I15/2, 2H11/2→4I15/2 and 4F9/2→4I15/2 separately. Due to concentration quenching phenomena, intensity of luminous bands gradually rises with the content of Er3+ doped ions up to 0.04 mol after that it starts to decrease regularly. Electric quadrupole-quadrupole interaction among the dopant ions was accountable for this quenching. Lifetime analysis confirms that the decay time is consistently declines with successive addition of trivalent erbium ions. This was due to the increment in the non-radiative path transitions. Suitable location of CIE point in the green region, high CCT and color purity values of the fabricated GdSr2AlO5:Er3+ phosphors endorse their probable utilization in field of solid state lighting.