Dinov was born to a Bulgarian family in Dedeagach in Western Thrace (today Alexandroupoli, Greece) and finished school in Plovdiv, Bulgaria. He studied at the Gerasimov Institute of Cinematography in Moscow under the tutelage of distinguished Soviet animators such as Ivan Ivanov-Vano. Dinov created his own first animated film, Yunak Marko (English: Marko the Hero), in 1955. Perhaps his best-known animated film in the West is the five-minute short Margaritka (English: The Daisy), produced in 1965. The film features a square-shaped little man trying to cut down a daisy and failing, then becoming more and more enraged as he tries increasingly brutal methods against the flower; in the end, the daisy only responds to the love of a child. Oddly, Margaritka won a prize for best children's film even though it was meant for adults.
He founded the first animation studio in Bulgaria, setting the highest quality professional standards for producing animation in his country. Later, he created the Animation Department (now a separate major) and taught animation classes at the Theatre and Film Arts Institute. Dinov was also a member of the Bulgarian Academy of Sciences.
In 1999, Dinov was awarded the highest-rank Bulgarian medal — the Stara Planina order (First Degree). In 2003 he received the Crystal Pyramide Award of the Bulgarian Filmmaker Union for lifetime achievement to the art of Bulgarian animation.
He died in Sofia at the age of 85.