Two-dimensional monolayers are a prime class of materials due to their extensive spectrum of applications. In the present study, the material characteristics of the 1T-Rb2Se monolayer are investigated and analysed by employing the first-principles DFT calculations. The computations of structural, electronic, bonding nature, dynamical, optical, thermoelectric, and elastic properties of the theoretically predicted 1T-Rb2Se monolayer are effectuated. The 1T-Rb2Se monolayer displays a semiconducting nature with the energy gap quantified using various exchange-correlational potentials. The phonon and CPMD was deployed for the conclusions on the dynamical and thermal stabilities. With indirect band gap and good thermal response, the material will have possible applications in photovoltaics and thermoelectrics. Positive Poisson's ratio and elastic tensors validates the elastic strength of the monolayer. The effective masses of charge carriers and its relative ratio are determined from the energy band paraboloids with the deformation potentials for the accuracy of the relaxation time. The 1T-Rb2Se is electronically, ionically, dynamically, thermally, and elastically stable that confirms its feasibility for experimental studies.