A series of 2-carbolinyl-carbapenems was prepared via the Stille stannane coupling reaction. This new class of antibiotics exhibited potent activity in vitro against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase negative staphylococci (MRCNS) as well as a broad spectrum of antibacterial activity. A high resistance to the mammalian dehydropeptidase, DHP-1, was also observed. Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase negative staphylococci (MRCNS) infections have increased dramatically in recent years. A program in these laboratories to investigate novel 2-aryl carbapenems with increased chemical and metabolic stability identified the meta-biphenyl pharmacophore of 1a as desirable for potent activity against gram-positive organisms including MRSA. Appending a 3-pyridyl moiety at the meta position of the phenyl ring as in 1b also achieved potent activity. Conformationally restricting the phenyl rings with a central five-membered ring connected through a heteroatom or with a carbonyl moiety provided various planar tricyclic structures 2 with increased anti-MRSA/MRCNS activity. To determine the cumulative effects of the meta-3-pyridyl ring of 1b and the planar tricyclic structure of 2, a series of 2-carbolinyl carbapenems (azacarbazoles) 3 were prepared with a nitrogen bridging the meta-biphenyl rings. The nitrogen of the pyridyl ring of 3 was introduced into all the four nonbridging positions to give the α, β, γ, and δ carbolinyl derivatives 3a-d and the quaternary analogs, 3e-i, were also prepared. Two α-carbolinyl analogs with the carboline attached at the 5-carbon, 4a, and the 7-carbon, 4b, were also prepared as well as the 9-des-methyl quaternary β-carbolinyl derivative 5. The above compounds were evaluated for antimicrobial activity in a primary antibacterial screen and the structure-activity relationships are presented. Of particular interest were the 1,9-dimethyl-α-carbolinyl-, 3e, the 2,9-dimethyl-β-carbolinyl-, 3f, and the 2-methyl-β-carbolinyl-carbapenem, 5, which all displayed excellent anti-MRSA/MRCNS activity as well as demonstrating a broad spectrum of antibacterial activity.