Theoretical calculations using density functional theory (DFT) both on semi empirical and Ab initio levels have been carried out for pyrromethene laser dye and related compounds (PM-chromophore, PM-4m, PM 546, PM650 PM 567 and PM597). We carried out theoretical calculations using DFT, AM1, TDDFT and CIS on ground and excited states for the selected laser dye materials, we obtained the optimized geometry of the molecules, UV, IR spectrum, and the transition between the ground S0 and the first excited S1 states exclusively, the HOMO and LUMO states and other properties.