A new Biginelli compound, C(18)H(25)BN(2)O(4)S(2), containing a boronate ester group was synthesized from a lithium bromide-catalysed reaction. The compound crystallizes with two independent mol-ecules in the asymmetric unit that differ mainly in the conformation of the ester functionality. The crystal structure is stabilized by inter-molecular N-H⋯O and N-H⋯S hydrogen bonds involving the 3,4-dihydro-pyrimidine-2(1H)-thione NH groups as donors and the carbonyl O and thio-phene S atoms as acceptors.