New unsymmetrically tetrasubstituted porphyrin-Schiff base ligands (8-10) containing recognition sites for alkali and transition metal quest cations have been synthesized by the condensations of 5-(4-aminophenyl)-10,15,20- triphenylporphyrin (5) with salycylaldehyde, 2-hydroxy-1-naphthaldehyde and 4'-hydroxy-5'-formyl-benzo-15-crown-5. Homonuclear crystalline 1:1 [Ni(II): ligand] complexes (8a-10a) of the ligands with Ni(CH2COO)(2). 4H(2)O have been obtained. The porphyrin ligands and their complexes have been characterized by elemental analysis, IR, UV-VIS, H-1, C-13 NMR and MS, and the structure of trans-5,15-bis(4-aminophenyl)-10,20-diphenylporphyrinato-nickel(II) (7a) has been examined crystallographically. It crystallizes in the monoclinic space group C2/c with a = 22.096(2), b = 13.455(1), c = 15.599(1) Angstrom, beta = 134.81(1)degrees, V = 3290.6(2) Angstrom(3), Z = 4 and D-x = 1.42 g cm(-3). The molecule is centrosymmetric and the porphine nucleus is non-planar. The average value for the diameter of the hole has been estimated as 3.830(4) Angstrom. (C) 2000 Elsevier Science B.V. All rights reserved.