The names of the two characters are diminutives of Bolesław and Karol. In English, the cartoon was distributed as Jym & Jam and Bennie and Lennie. Some episodes were seen as part of Nickelodeon's Pinwheel. In 1973 the creators of the film placed on the request from the female viewing audience a girl character by the name of Tola. The first time she appeared in occurred in the episode entitled "Tola". In total, Tola appeared in 30 episodes.
Most episodes do not have dialogues. Exceptions are feature-length films and the series from the 1980s, where the main characters' voices were done by: Bolek - Ewa Złotowska, Ilona Kuśmierska; Lolek - Danuta Mancewicz, Danuta Przesmycka.
During the period of the Peoples Republic of Poland (PRL), Bolek and Lolek were reproduced in a large quantity of toys: action figures, movies, postcards, online arcades, puzzles, etc., which can be seen in the Museum of Dobranocek (bed-time stories) of the PRL. They are also currently made in computer programs, coloring books, general picture books and games.
Of all the Polish animated cartoons Bolek and Lolek ranks as number one all-time favorite. The series was popular in many countries, and was one of the few animated movies allowed to be broadcast by Iranian television just after the revolution of 1979.