Abstract: The BESⅢ Collaboration has recently embarked on a two-photon physics program. Its main motivation is given by the large uncertainty of the contribution of hadronic light-by-light scattering to the anomalous magnetic moment of the muon α_μ, and the need of electromagnetic transition form factors(TFF) as experimental input to improve the calculations. Data acquired with the BESⅢ detector at center-of-mass energies from 3.77 to 4.6 GeV allow for the determination of TFFs of light pseudoscalar mesons. The measurements are performed with a single-tag technique and result in unprecedented accuracy at momentum transfers below 2 GeV², the region of highest importance for the calculations of α_μ. Employing the same approach, the first double-tagged measurement of the pion transition form factor has been started. It is the first step towards a model independent parameterization of the TFF of the π⁰. Additionally, measurements of multi-meson final states have been engaged.