Luminescence spectra of two square-planar dithiocarbamate complexes of platinum(II) with different steric bulk, platinum(II) bis(dimethyldithiocarbamate) (Pt(MeDTC)(2)) and platinum(II) bis(di(o- pyridyl)dithiocarbamate) (Pt(dopDTC)(2)), are presented at variable temperature and pressure. The spectra show broad d-d luminescence transitions with maxima at approximately 13500 cm(-1) (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt(dopDTC)(2). Luminescence maxima of Pt(MeDTC)(2) shift to higher energy as temperature increases by +320 cm(-1) for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm(-1) on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt(dopDTC)(2) shift in the opposite direction by -460 cm(-1) for a temperature increase by 200 K. The bandwidth of approximately 2900 cm(-1) does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 +/- 3 and +11 +/- 1 cm(-1)/kbar, for Pt(MeDTC)(2) and Pt(dopDTC)(2), respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt(MeDTC)(2).