Limitation on C=N → B–O complex formation for isoindigo derivatives and its neglectable electron-withdrawing add-on effect

Attempts to merge three isoindigo derivatives, namely diazaisoindigo (DAII), thiazoloisoindigo (TzII) and hydroxyisoindigo (OHII), with CN → B–O complex for stronger acceptors show that only OHII can form stable CN → B–O complexation, however, no obvious electron-withdrawing capability enhancement was observed.