Dye doped polymer films of poly(methyl methacrylate) (PMMA) and brilliant cresyl blue (BCB) dye were synthesized using the solution casting technique. This work aims to investigate the influence of BCB dye doping on the structural, optical, dielectric and mechanical properties of PMMA. XRD reveals an increase in PMMA amorphicity with BCB loading. This suggests the solubility of BCB dye within PMMA. Fourier transform IR confirms the interaction between BCB dye and PMMA. The transmittance T of PMMA decreases with BCB doping and the cut‐off transmission occurs in the ranges 200–366 nm and 560–660 nm for 2 wt% BCB doped film. The absorbance of PMMA deceases with λ and loading BCB creates many absorption edges. The optical bandgaps of dye doped films are lower than that of PMMA. Urbach's energy increases from 0.52 to 0.86 eV on BCB doping. The dielectric constant ε′, dielectric loss ε″ and AC conductivity σ_ac at room temperature as a function of frequency f, 100 Hz to1.0 MHz, and the doping level were studied. Loading dye increases σ_ac to higher values. The optical limiting results indicate that the dye doped films are highly attenuated for a laser beam of 638.2 nm. The dye incorporation enhances the mechanical performance of PMMA. It increases Young's modulus, tensile strength and elongation at break, which boosts the use of 1 wt% BCB doped film as a flexible laser attenuator. The excellent characteristics of novel BCB dye doped PMMA films present them as cut‐off laser filters, laser attenuators, optoelectronic devices or in the semiconductor industry. © 2020 Society of Industrial Chemistry