He met the French zoologists Louis Fage (1883–1964), Édouard Chatton (1883–1947), Charles Pérez (1873–1952) and Jules Richard (1863–1945).
On the intervention of Grigore Antipa (1867–1944), in 1940 Băcescu was transferred from the University of Iaşi to the National Museum of Natural History in Bucharest.
Băcescu participated in several scientific expeditions to the coasts of Peru and Chile (1965), Mauritania (1975), Arabia (1977) and Tanzania (1973–1974).
He was a member of the Romanian Academy, and of the French Society of Zoology and Director of the Institute of Oceanography Albert 1er in Monaco.
He was also the author of numerous books on the ecology of the Black Sea, the fauna of Romania, bioethnology, etc.. As a tribute to his work, more than 70 taxa have been dedicated to him by various scientists.