This study describes the synthesis of bicyclic glutamate analogues CIP-A [(±)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazole-3,4-dicarboxylic acid, (±)-5] and CIP-B [(±)-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazole-3,6-dicarboxylic acid, (±)-6] via a key 1,3-dipolar cycloaddition reaction of ethoxycarbonylformonitrile oxide (generated in situ from ethyl 2-chloro-2-(hydroxyimino)acetate) to a suitably protected racemic 3,4-didehydroproline. The biological profiles of these compounds at glutamate receptors were evaluated using in vitro assays (receptor binding with [³H]AMPA, [³H]KAIN, [³H]CPP; second-messenger studies on mGlu1, mGlu2, mGlu4a receptors expressed in CHO cells; and rat cortical wedge electrophysiology) and in vivo convulsant activity tests in DBA/2 mice (a model for AMPA/KAIN receptor-mediated seizures). Neither compound showed significant activity at the tested metabotropic glutamate receptors. CIP-A exhibited high affinity for AMPA (IC₅₀: 1.3 ± 0.5 µM) and KAIN (IC₅₀: 0.48 ± 0.11 µM) receptors, no affinity for NMDA receptors (IC₅₀ > 100 µM), and potent in vivo convulsant activity (icv CD₅₀ for clonus: 0.027 nmol/mouse), with its excitatory effects antagonized by the AMPA/KAIN antagonist NBQX but not the NMDA antagonist CPP. CIP-B bound to AMPA (IC₅₀: 24.7 ± 6.2 µM), KAIN (IC₅₀: 48.0 ± 4.4 µM), and NMDA (IC₅₀: 23.0 ± 3.6 µM) receptors but had lower excitatory (EC₅₀: 284 ± 30 µM) and convulsant activity. The 3-carboxyisoxazolinyl moiety in these analogues appears critical for interacting with both AMPA and KAIN receptors, and CIP-A's potent convulsant activity may stem from synergistic action at these receptors. Future work on enantiomer synthesis, conformational analysis, and pharmacokinetic properties will further clarify receptor selectivity and activity mechanisms.