[DafoneH-2][(CuCl3H2O)]Cl (dafone = 4,5-diazafluoren-9-one) crystallizes in the monoclinic space group P2(1)/c with a - 14.585(2) angstrom, b - 14.143(7) angstrom, c = 7.076(6) angstrom, beta -91.3(2)-degrees, and Z = 4. The crystal contains the unusual chromophore [(CuCl3H2O)Cl]2- showing coordinated water and a semicoordinate Cl-. Moderately strong antiferromagnetic exchange (J = -72.8 K, with H(ex) = -2JS1S2) is present. The exchange pathway appears to be via an H-bond involving H2O and Cl- of inversion-related molecules. Cl...Cl contacts also exist, but on the basis of geometry, EHMO calculations, and comparison with other systems, they are ruled out as the main exchange pathway. Single-crystal EPR studies (g1 = 2.069, g2 = 2.089, g3 = 2.250) show further weak exchange via H-bonding between the semicoordinate Cl- and H2O.