Complex sentence: Library East (now Smathers Library) was at the same time designated as the undergraduate library, however in the following decades the two buildings' collections were integrated and Library West became established as the social sciences and humanities library on campus.
Split into simpler sentences: Library East (now Smathers Library) was at the same time designated as the undergraduate library. However, in the following decades the two buildings' collections were integrated together and Library West became established as the social sciences and humanities library on campus.