A new molecular conductor (PyMe)[Ni(dmit)2]2 (PyMe=N-methylpyridinium, dmit= 2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and its structure been determined. The temperature-dependent conductivities in the range of 290-20K reveal a semi-conducting behavior of the crystal with a small activation energy of 0.067 eV and a quite high room temperature conductivity of 2 Scm 1.

We have synthesized a series of new D−π−A compounds that feature various electron donors and a fixed benzothiazolyl unit as an electron acceptor. The crystal structure of compound 3 [trans,trans-2-{4-[(4-N-carbazolyl)styryl]styryl}-1,3-benzothiazole, CSSB] was determined. All these compounds show high fluorescence quantum yields and 3 in toluene gives the most intense blue emission around 450 nm with a quantum yield of Φ = 0.69. When excited at 800 nm by a Ti: sapphire femtosecond laser, these compounds exhibit strong two-photon-excited fluorescence (TPEF) in the blue-to-orange region. The measured TPEF cross-section of compound 2 [trans,trans-2-{4-[4-(N,N-diphenylamino)styryl]- styryl}-1,3-benzothiazole, DPSSB], for example, is about 6.1 times that of Coumarin 307. hotophysical data indicate that these compounds are polar in the ground state and have an enhanced polarity in the excited state, and that the electron donating ability of a dialkylamino group is much stronger than that of a diarylamino group.

A new molecular conductor PyH[Pd(dmit)2]2 (PyH=pyridinium, dmit=2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and structurally investigated. The room temperature conductivity at a certain direction on (001) plane was measured to be as high as a 2

Three compounds with three p-substituted styryls attaching to the central s-triazine have been synthesized and two crystals determined to be in non-centrosymmetric Cmc21 and Pmn21 space groups, respectively. All of them in solid state are second harmonic generation (SHG) active and two of them show powder SHG intensities one order of magnitude that of urea.

Electrically conductive platelet crystals of Z[Pd(dmit)2]2 [Z = (Me3NEt), (MeNEt3), (NEt4)], as well as their precursors Z2 [Pd (dmit) 2], have been synthesized by a non-electrochemical method and their structures have been determined. The single-crystal conductivities at a direction on the cleavage surface at room temperature were measured to be 58 Ω 1 cm 1 for (Me3NEt)[Pd(dmit)2]2, 5.0 Ω 1 cm 1 for (MeNEt3)[Pd(dmit)2]2 and 2.2 Ω 1 cm 1 for (NEt4)[Pd(dmit)2]2, respectively. This sequence of conductivity is agreement with the sequence of structural twodimensionality of these three complexes. The resistivity–temperature curves reveal the semiconducting behavior of the above complexes, which show very narrow band gaps. The structure analysis results reveals that when the size of cation Z in Z[Pd(dmit)2]2 is finely tuned [(Me4N)+→(Me3NEt)+→(Me2NEt2)+→(MeNEt3)+→(NEt4)], the corresponding complexes belong to the same structural motif and each individual possesses some special structural characteristics. Subtle structural difference in this group of complexes can severely influence their measured conductivities and significantly influence their calculated band structures.