From the discovery of the first effective antiviral nucleoside compound [1], synthesis and investigation of nucleoside analogues, especially acyclic ones, attracts constant attention. The 5, 6-double bond modification of pyrimidine ring in DNA bases causes a change of planar aromatic ring into non-planar 5, 6-dihydropyrimidine ring. The investigations of biological activity evidenced that 5, 6-dihydronucleosides are also potent antiviral agents, and some of them have similar antiviral activity as AZT [2]. In continuation of our previous study [3], in this contribution will be discussed structural properties and supramolecular assembling of aliphatic bicycle anhydro 5, 6-dihydrothimine derivative 1 and the products of the oxazolidine ring-opening 2 and 3 in the solid state (Scheme 1). Conformation of dihydropyrimidine ring in 2 and 3 is half-chair, while in bicycle derivative 1 is half-boat. Intermolecular interactions in 3 (Fig. 1) and 2 (Fig. 2) form two-dimensional and three-dimensional networks, respectively. Compared to 3, one weak C-H...Pi interaction in bicycle derivative 1 extends two dimensional network into three-dimensional, so playing a crucial role in the formation of higher-order supramolecular structure (Fig. 3). References: [1] Prusoff, W.H. (1959) Biochim. Biophys. Acta 32, 295–296. [2] Duschinsky, R., Gabriel, T., Tautz, W., Nussbaum, A.W., Hoffer, M. & Grunberg, E. (1967) J. Med. Chem. 10, 47–58. ; Jan, S.-T., Shih, M.-J., Venkatachalam, T.K., Cruz, O.J.D., Chen, C.-L. & Uckun, F.M. (1999) Antivir. Chem. Chemother. 10, 39–46. [3] Cetina, M., Makarević, J. & Nura-Lama, A. (2010) J. Mol. Struct. 980, 156–162.