Discotic mesogens containing the benzo[e][1,2,4]triazinyl radical as the central unit exhibit a Col(h) phase below 80 degrees C. Depending on the substituent at the N(1) position, they show different modes of thermal expansion and magnetic behavior, presumably due to differences in molecular organization. Thus, for 1-phenyl (1a) and 1-PhF-m (1b) derivatives, the Col(h) phase has positive thermal expansion coefficient kappa and antiferromagnetic interactions, while for the 1-(3,4,5-(C12H25X)(3)C6H2) derivatives 1c (X = O) and 1d (X = S), kappa is negative and weak ferromagnetic interactions in the crystalline phase are observed for 1c (j/k(B) = +4.76 K). Compounds 1a and 1c exhibit photoinduced hole transport (mu approximate to 1.3 X 10(-3) cm(2) V-1 s(-1)) in the Col(h) phase.