Contribution
Boyle mainly studied gases. He discussed the possibility of atoms existing, however his work was greatly impeded by the church. He attempted alchemy or turning regular metals into gold. He made gas chambers to study from. Unlike the greek philosophers, he was doing physical experiments. He proposed that elements are composed of 'corpuscles' of various types and sizes that are able to organize themselves into groups that represent different chemical substances. He also was able to distinguish between a mixture and a compound.
Significance of Contribution
He stressed organization of atoms/'atomos'/'corpuslces' and is sometimes called the Father of Chemistry for his extensive work on materials.
fun fact
He was an accomplished author of both science papers and morality books.