INTRODUCTION -- PART A: N-ACYLCYANAMIDES AS NEW PARTNERS IN RADICAL CASCADES: SYNTHESIS OF POLYCYCLIC QUINAZOLINONES AND GUANIDINES -- THE CYANAMIDE MOIETY, SYNTHESIS AND REACTIVITY -- HOMOLYTIC AROMATIC SUBSTITUTIONS: STATE OF THE ART OF THE MECHANISTIC PROPOSALS -- RESULTS: DEVELOPMENTS OF NEW RADICAL CASCADES WITH N-ACYLCYANAMIDES -- OBJECTIVES OF THE PROJECT -- ADDITION OF ALKYL RADICALS -- ADDITION OF VINYL RADICALS TO N-ACYLCYANAMIDES -- ADDITION OF NITROGEN CENTERED RADICALS -- PREPARATION AND CYCLIZATION OF ALKYL PRECURSORS -- PREPARATION AND CYCLIZATION OF VINYL PRECURSORS -- PREPARATION AND CYCLIZATION OF AZIDE PRECURSORS -- PART B: VISIBLE-LIGHT PHOTOREDUCTIVE CATALYSIS FOR AN ECO-COMPATIBLE GENERATION OF RADICALS -- BIBLIOGRAPHICAL BACKGROUNDS: GENERATION OF RADICALS BY VISIBLE LIGHT PHOTOREDOX CATALYSIS -- PHOTOPHYSICAL PROPERTIES OF TRIS(BIPYRIDYL)RUTHENIUM(II) COMPLEXES -- STATE OF THE ART OF THE SUBSTRATES AMENABLE TO VISIBLE LIGHT PHOTOREDOX CATALYSIS -- RESULTS: VISIBLE LIGHT-INDUCED PHOTOREDUCTIVE GENERATION OF RADICALS FROM EPOXIDES AND AZIRIDINES -- EPOXIDES AS NEW SUBSTRATES FOR VISIBLE-LIGHT TRIGGERED GENERATION OF RADICALS -- SCOPE AND LIMITATIONS OF THE REDUCTIVE RING-OPENING METHODOLOGY -- UTILIZATION OF THE PHOTOGENERATED RADICALS IN CARBON-CARBON BOND FORMATIONS -- SUPPORTING INFORMATION -- GENERAL REMARKS -- GENERAL PROCEDURES -- EPOXIDE, AZIRIDINES AND CYCLOPROPANES PRECURSORS -- REDUCTIVE RING-OPENING PRODUCTS -- ALLYLATION PRODUCTS 246 -- PART C: NEW DEVELOPMENTS IN ARYL-ARYL COUPLINGS VIA PALLADIUM/NORBORNENE DUAL CATALYSIS: SYNTHESIS OF PHENANTHRIDINES AND PHENANTHRENES -- BIBLIOGRAPHICAL BACKGROUND: THE ORTHO EFFECT IN THE CATELLANI REACTION -- THE CATELLANI REACTION -- SYNTHETIC APPLICATIONS OF THE ORTHO EFFECT -- MECHANISTIC EXPLANATIONS FOR THE ORTHO EFFECT -- RESULTS: NEW PARTNERS FOR ORTHO-SUBSTITUTED ARYL IODIDES IN PALLADIUM/NORBORNENE COCATALYSIS -- COUPLING OF ORTHO-SUBSTITUTED ARYL IODIDES AND BROMOBENZYL AMINES: FIRST REPORTED CATELLANI SEQUENCETERMINATED BY N-ARYL COUPLING WITH UNPROTECTED AMINES -- COUPLING OF ORTHO-SUBSTITUTED ARYL IODIDES AND 2-BROMOPHENYL ACETAMIDES: AN EXCEPTION TO THE ORTHO EFFECT -- SUPPORTING INFORMATION -- GENERAL REMARKS -- COUPLING OF ORTHO-SUBSTITUTED ARYL IODIDES AND BROMOBENZYL AMINES -- COUPLING OF ORTHO-SUBSTITUTED ARYL IODIDES AND 2-BROMOPHENYL ACETAMIDES.