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FTIR spectra of pyridine-2, 3-dicarboxylic anhydride (2, 3-PDA) and pyridine-3,4-dicarboxylic anhydride (3, 4-PDA) isolated in argon and nitrogen matrices at $15\circ K$ have been obtained. Mild photolysis $(\ast \ge 340nm)$ of modest duration readily produces CO and $CO2$ fragment absorption, plus bands of $-C\equiv C-$ character due to transient species. Since neither terminal $-C\equiv N$ nor $-C\equiv C-H$ frequencies are present, we believe that the intermediates are cyclic in nature; perhaps pyridyne. (Corresponding experiments with phthalic anhydride yield benzyne.$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$) Additional photolysis of the matrix isolated samples, however, produces new decomposition products including HCN and diacetylene. The vibrational spectra of the transient intermediates from 2,3-PDA and 3,4-PDA are quite different in their frequencies and intensities, which suggests that the photolysis products from the two precursors are different in nature. The experimental results will be presented, and interpreted in terms of normal coordinate analyses and considerations of the interactions between the nonbonding electrons of the nitrogen atom and the sp2 orbitals of neighboring dehydrogenated carbon atoms. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$ H.-H. Nam and G. E. Leroi, Spectrochim. Acta 41A, 67 (1985); J. Mol. Structure (1987), in press.