[1] He is recognized in the fields of porphyrinoid chemistry for his works in extended π-electron systems and its tunable aromatic behaviors.

From 2001 to 2007, Osuka was the Project Leader of "Creation of Bio-devices and Bio-systems with Chemical and Biological Molecules for Medical Use" at the Japan Science and Technology Agency.

[1][13] On the occasion of his 65th birthday and his retirement, in 2020, from Kyoto University, a special issue of the Journal of Porphyrins and Phthalocyanines was dedicated to honouring Osuka and his achievements.

As a mark of respect for his work in this field, T. K. Chandrashekar and J. Sessler were among the fifty-five scholar-contributors who submitted their research papers to be published in his honour.

Osuka's influence in the field of porphyrin chemistry, due to his scientific discoveries, were mentioned in the foreword to the issue.