The decay mode ψ′→γγψ has been studied with the Mark-II detector at SPEAR. New measurements of branching ratios for decays of the type ψ′→γχ, χ→γψ involving known χ states are presented. The existence of a χ state of mass near 3455 MeV/c2 produced in this decay chain is not confirmed, and the upper limit (90% confidence level) of the product of branching ratios is measured to be 0.13%. A new decay mode, ψ′→π0ψ, which violates isospin conservation is observed with branching ratio (0.15±0.06)%. © 1980 The American Physical Society.