To understand the effect of inserting different metals into porphene, we have investigated 36 first row metalloporphenes in their D2h and D4h minima. These metalloporphenes can be described with the general formula 2S+1 M(q)XP, where the metal M, which is in oxidation state q, ranges from Sc to Zn. X denotes the axial ligand (oxide or chloride, if present) and 2S+1 the unit cell multiplicity. In addition to band structures, we report the band gap Eg, effective masses me (in semiconductors) and conductivity (in gapless systems), the energy difference between the lowestenergy D2h and D4h geometries (when they are distinct), and the work function. Finally, the variation in C-C bond lengths is described with a modified HOMA. Further details are given in the experimental section.