The following derivatives of 7-hydroxytetrahydroisoquinoline-3-carbox acid {Tic(OH) [I]}, a conformationally restricted analogue of tyrosine, were synthesized for the purpose of photophysical studies and in order to elucidate the nature of tyrosine fluorescence and its decay : Ac-Tic(OH) [II], Ac-Tic(OH)-NHMe [III], Tic(OH)-NHMe [IV], Ala-Tic(OH) [V], Ac-Ala-Tic(OH) [VI], and Tic(OH)-Gly-NH2 [VII]. For the simple Tic(OH) derivatives I-IV, the N-methylamide was found to be a more effective quencher than the acetyl group. For the peptidic derivatives V-VII the highest quenching of the fluorescence of the phenolic chromophore was observed in the case of Ala-Tic(OH). The simple Tic(OH) derivatives I-IV were also the subject of theoretical studies (MOPAC 93). The obtained thermodynamic parameters (MOPAC calculations) and the fluorescence components were discussed on the basis of the rotamer theory in order to explain the participation of an individual rotamer in the complex process of the fluorescence decay of tyrosine.