The invention comprises compositions and methods useful for encapsulation and controlled release of guest molecules, such as drugs. Compositions of the present invention comprise a matrix comprising molecules that are non-covalently crosslinked by multi-valent cations, wherein the molecules that are non-covalently crosslinked are non-polymeric, have more than one carboxy functional group, and have at least partial aromatic or heteroaromatic character The compositions are characterized in that a guest molecule may be encapsulated within the matrix and subsequently released.