The complexes (dppe)M{S2C2(2-pyridine)(CH2CH2OC(O)CH3)} (dppe = 1,2-bis(diphenylphosphino)ethane; M = Pd, Pt) were prepared from 1-(2-pyridyl)-4-acetoxy-2-bromobutan-1-one and the corresponding (dppe)M(SH)(2) complexes. The acetyl group was removed from the metal complexes to yield the corresponding alcohols, (dppe)M{S2C2(2-pyridine)(CH2CH2OH)}. The lauroyl derivatives (dppe)M{S2C2(2-pyridine)(CH2CH2OC(O)(CH3)} were prepared by esterifying the alcohols with lauroyl chloride. The alkylated pyridinium complexes [(dppe)M{S2C2(CH2CH2-N-2-pyridinium)}](+) were generated by the addition of either p-toluenesulfonyl chloride or bis(triazole) o-chloroaryl phosphate to (dppe)M{S2C2(2-pyridine) (CH2CH2OH)). [(dppe)Pd{S2C2(CH2CH2-N-2-pyridinium)}][BPh4] crystallizes in the P (1) over bar space group with a = 9.1924(2) Angstrom, b = 16.0191(2) Angstrom, c = 17.4368(3) Angstrom, alpha 106.292(2)degrees beta = 96.235 degrees, and gamma = 95.183(2)degrees. The molecule is best described as a square planar palladium complex with a planar metallo- 1,2-enedithiolate which is coplanar with the alkylated pyridinium. The pyridinium-substituted platinum 1,2-enedithiolate complexes have a 1,2-enedithiolate to heterocycle pi* charge transfer transition (ILCT) that is the lowest lying band. Like [(dppe)Pt{S2C2(2-pyridinium)(H)}](+), [(dppe)Pt(S2C2(CH2CH2-N-2-pyridinium)}](+) is luminescent in room-temperature solution with two emissive states assigned to the ILCT* singlet and triplet. The lifetime of the (ILCT)-I-1* is 0.2 ns, (1)phi = 0.002, while the lifetime of the (ILCT)-I-3 is 8.3 mu s, (3)phi = 0.01 (DMSO). While [(dppe)Pt{S2C2(CH2CH2-N-2-pyridinium)}](+) is emissive, the [(dppe)Pt{S2C2(2-pyridinium)(CH2CH2OR ")}](+) complexes are weak emitters at best in solution with triplet quantum yields of < 0.0001 (DMSO). These photophysical studies suggest that the heterocycle and the 1,2-enedithiolate must be coplanar in the ILCT excited states for the complexes to be emissive in room-temperature solution.