Energy Band and Conductivity of（PyH）［Ni（dmit）2］2

As theoretical approach for synthesized molecular conductor（PyH）［Ni（dmit）2］2，two-dimensional energy bands have been calculated by using EHMO tight binding method. Intermolecular HOMO-HOMO overlap integrals of various［Ni （dmit）2］-0.5 ?［Ni（dmit）2］-0.5 pairs in the two-dimensional conductive network have also been calculated. The calculated energy gap 0.17 eV is in accord with the measured conducting activation energy 0.15 eV，indicating that（PyH）［Ni（dmit）2］2 is a semiconductor with the narrow energy gap. Based on energy band calculation，the structure-properties correlations have been discussed. Among various structural factors，the uniformity and the compactibility of the array of the［Ni（dmit）2］-0.5 play a crucial part in influencing the conductivity of the（PyH）［Ni（dmit）2］2 crystal.