AbstractA study of photo‐induced electron‐transfer reactions in MeCN with 9,10‐dicyanoanthracene as acceptor and 21 electron donors with transient photoconductivity measurements is reported. The free‐ion yield and the rate constant of back electron transfer are determined. For exergonic reactions, the ‘Marcus‐inverted’ region is observed. The fit with the theory is best, when a nearly solvent‐independentCoulombterm is used in the calculation of the