The unprecedentedly undissociated HCl hydrates, and unconventional cis-linear conformation of the water dimer at ambient condition were found in a novel organic crystal by direct crystallographic evidences. The peculiar tricyclo[6.2.0.0]-type configuration of hydrogen-bonding network induces such unexpected undissociated HCl hydrates, and unusual cis-linear conformation of the water dimer. (C) 2016 Elsevier B.V. All rights reserved.