The photolysis of 10,10′-disubstituted 9,9′(10H,10′H)-biacridinylidenes afforded the corresponding 7,16-dihydrobenzo[1,2,3-kl:6,5,4-k′l′]diacridines. The formation of photocyclized dihydrophenanthrene-type intermediates was confirmed spectroscopically.
                                    10,10′-二取代9,9′(10H,10′H)-双
吖啶亚基的光解作用产生了相应的7,16-二氢苯并[1,2,3-kl:6,5,4-k′l′]二
吖啶。光环化二氢
菲类中间体的形成通过光谱学得到了证实。