We have synthesized two boron complexes of 3‐(o‐hydroxyphenyl)imidazo[1,5‐a]pyridine exhibiting blue emission in solution. The transient absorption and theoretical studies of the complexes and their 1‐(o‐hydroxyphenyl) substituted isomers revealed that the phenolic substituent position in boron complex of imidazo[1,5‐a]pyridine affected the excites state dynamics involved in photoluminescence (PL). Although the introduction of phenolic substituent at 1‐position of the boron complex is effective to achieve the strong emission, the introduction of phenolic substituent at 3‐position results in the decreasing PL quantum yield due to intersystem crossing from the singlet excited state to the triplet excited state.

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