The present invention relates to certain compounds of Formula (Ia) and pharmaceutically acceptable salts thereof, which exhibit useful pharmacological properties, for example, as agonists of the S1P1 receptor: Also provided by the present invention are pharmaceutical compositions containing compounds of the invention, and methods of using the compounds and compositions of the invention in the treatment of S1P1 receptor-associated disorders, for example, a disease or disorder mediated by lymphocytes, an autoimmune disease or disorder, an inflammatory disease or disorder, an inflammatory skin disease or disorder, cancer, psoriasis, atopic dermatitis, rheumatoid arthritis, Crohn's disease, transplant rejection, multiple sclerosis, systemic lupus erythematosus, ulcerative colitis, type I diabetes, and acne, microbial infections or diseases and viral infections or diseases.